Crime Scene Investigation

Crime Scene Investigation

Scenario Police have been called to a one-room apartment to investigate a possible homicide. The body is on the floor near the center of the room with what appears to be a single gunshot to the head. The suspected weapon is lying nearby. Describe how you would go about investigating this scene, with particular reference to establishing the integrity of the crime scene, safety and contamination of any evidence.

Principles of Crime Scene Investigation Preserving the Integrity of the Crime Scene Recording the Crime Scene Searching the Scene Collecting & Packaging of Evidence Crime Scene Safety The most important aspects of CSI work include: Securing the scene Prevention of contamination Preservation of physical evidence

The Crime Scene Environment Crime Scene Investigators (CSIs) interact with: Police officers (including general duties, investigative, specialist and administrative areas Some CSIs are police officers/some are civilian) The judicial system including: legal practitioner, (prosecution and defense lawyers) judges and courts (including civil, coronial, criminal and appeal Courts) Forensic scientists (including specialist laboratories and experts)

Forensic medical practitioners (including pathologists, psychologists and psychiatrists) General community often represented through juries, including those involved in specific incidents (victims, suspects, witnesses) and expectations shaped by media reporting of actual cases, fictional material, (books, magazines, television and movies). CSI Effect!

Role of the Crime Scene Investigator Establish clear and direct lines of communication and be effective managers: At the scene of the crime or incident Of the processing of physical evidence collected from the scene Of the investigative process as it relates to physical evidence Of the final presentation of physical evidence at court Crime scene investigators conduct the initial examination of the scene to ensure that all physical evidence is collected and processed. Beyond the scene, further evidence may become available (e.g. from the offender). The coordination of how this evidence is collected, processed and presented to Court will have important scientific and legal implications. communication begins from initial notification of the crime or incident, attending the scene, through the various phases of the investigation, to the final presentation of evidence at Court and (any subsequent appeal). CSI perform the technical aspects of collecting, recording, examining, and analyzing physical evidence as an integral part of the investigating team

When investigating, the CSI should consider: Use an entry other than that taken by the suspect Establish the path taken by other persons first on the scene Consider the loss of trace evidence on entry throughout your examination, (e.g.. shoe/foot impressions on the floor) Securing the Scene Personnel responding to a crime scene must approach and enter the scene cautiously while being aware of the presence of personnel, vehicles, ongoing events, any potential evidence, and the environmental conditions. They should be aware of the possibility of secondary, or multiple crime scenes, and any initial observations such as the presence of distinctive odors, sounds, etc. At this time, the investigator should assess the site and give consideration to any safety measures that need to be taken to protect themselves and other personnel.

Reassess Occupational Safety and Health (OSHA) issues Establish the extent of the scene and additional assistance that may be required Establish an entry and exit path for the Senior Investigating Officer and specialists to access the scene, if necessary On initial entry into the scene, the crime scene investigator should proceed with great caution, keeping in mind the potential to destroy evidence at the scene. A plan should be formulated to minimize destruction of evidence by considering the initial physical approach.

Boundaries usually start at the focal point of the scene and extend outward to include: Where the crime occurred Potential points of entry and exit of suspects and witnesses Places where the victim or evidence may have been moved

The basic protocol for scene processing can be summarized as several sequenced tasks: Survey the crime scene Photograph the crime scene Map and measuring the crime scene Record and document the location of physical evidence at the crime scene Searching for fingerprints and other physical evidence. *During the walk-through, a walkway other than the established path of entry should be used to reduce contamination.

There are generally 6 important categories of documentation that are applicable to any search: Administrative Worksheet Narrative Description Photographic Log – overview, specifics Diagram/Sketch – scaled sketch Evidence Recovery Log - Identify, Collect and Preserve evidence Latent Print Lift Log The purpose and goals behind their use are usually identical from one agency to another. These documents may include body outlines for recording injuries, clothing outlines for recording damage or staining, and data analyses sheets for the simple recording, reference to, and interpretation of basic laboratory and presumptive tests.

Approach to Searching Consider the nature of physical evidence and the principles of exchange and transfer. (Locard) Each scene is unique and must be approached with an open mind. Measuring/Sketching a Crime Scene Measuring a crime scene and preparing accurate scale or sketch plans can be of great assistance in a criminal investigation. Your organization may or may not require you to measure and prepare scale plans for a crime scene. In any case, one of the most practical and helpful ways of taking crime scene notes is to sketch the scene and you should endeavor to develop skills that will allow you to prepare sketches of scenes. A CSI recollects a question posed by a police officer at a murder scene who asked, “Can I help? Tell me what you are looking for?” The crime scene investigator responded, “I don’t know exactly what I am looking for, but I will know when I find it.”

The most transient evidence should always be collected first, progressing to the least transient evidence. Moving from the least intrusive collection techniques to the most intrusive techniques. When processing the scene, the scientist should select a progression of processing and collection methods so that initial techniques do not compromise subsequent processing or collection methods.

The collection of evidence must be documented, by recording its location at the scene, the date of collection and who collected it. For each item collected, a chain of custody must be established.

List of evidence collection guidelines for: Bloodstains Seminal stains Hair Fibers Glass Paint Flammable liquids Firearms evidence Tool marks Controlled substances & medicinal preparations Questioned documents Latent fingerprints

3 Methods to adopt in your approach to searching Positive Approach – what is there Negative Approach – what isn’t there Information/Intelligence Positive - “There is nothing like first-hand evidence.” (Doyle, 1947) This approach to searching is to find evidence at a crime or incident scene that will provide physical evidence about the case under investigation. E.g. murder weapon, relevant blood stained clothing or trace evidence - this is, a positive search. Negative: “One should always look for a possible alternative and provide against it. It is the first rule of criminal investigation.” (Doyle, 1947) This approach to searching is to determine that something was not there. E.g. the absence of a forced entry at a murder scene could indicate that the victim may have known the offender. The absence of skid marks at the rear wheels of a vehicle, involved in a collision may indicate a lack of action or inattention by the vehicle driver to stop the vehicle prior to impact. Information/Intelligence: The crime scene investigator should look at a variety of possible explanations of the known facts and use intelligent thought and concentration to further assess the correctness of the information received.

The positive search which centers on known facts to locate evidence which is expected to be found (the tool mark in the scenario) The negative search, which centers on known facts to indicate that no evidence, was found to indicate an alternate explanation (e.g. could the suspect have entered through another door) A crime scene investigator who attended the scene of a break and enter proved an example of this application. The investigating officer told the crime scene investigator that a likely suspect had been arrested. The investigating officer indicated that the offender had cut through and removed the staple section of a sliding bolt thus disabling the padlock, which secured the front door to the premises. The senior investigating officer indicated that a pair of pliers had been found on the suspect and it was likely that a tool mark comparison could be made of the pliers and the cut staple.

The intelligent search which requires a combination of known facts, consideration for other explanations and a systematic and thorough approach to locate any other evidence (finding of the tip of the pliers, based on information about a pair of pliers) The CSI attended the scene, examined the cut staple and took the usual notes, photographs etc. The pliers had not been viewed by the crime scene investigator at this stage. It seemed that the only evidence available would be a comparison analysis of the tool mark and pliers (which is not always conclusive). However, a thorough search of the floor indicated a far more convincing and positive item of evidence, a small broken fragment of metal. The fragment of metal was collected. Later that day the crime scene investigator was handed the pair of pliers that were found on the suspect. The pliers were examined closely and the tip of one of the jaws was missing. The metal fragment collected from the scene was found to be the tip of the missing jaw.

Searching Patterns or Methods There are 5 basic methods that are universally accepted. These are: Line/Strip method Spiral method Wheel/Ray method Grid method Quadrant/Zone method

Line/Strip Search Pattern --One or two investigators start at the boundary of the crime scene and search in straight lines across to the other side of the crime scene. Grid Search Pattern -- Two or more investigators form a grid by searching in line patterns that overlap and are perpendicular to each other.

Spiral Search Pattern --One investigators searches in a spiral path from the center of the crime scene to the boundary (outward) or from the boundary of the crime scene to the center (inward). Wheel/Ray Search Pattern --Several investigators search in straight lines from the center to the boundary (outward) or from the boundary to the center (inward). Quadrant/Zone Search Pattern --The crime scene is divided into smaller sections (zones). One or more investigators are assigned to search each zone.

The area(s) to be searched will often be determined by the: Nature of the incident Nature of the physical evidence present Location Terrain Established facts

The Golden Rules of a Search 3 Golden Rules to maximize the recovery of evidence: 1. Search areas should be determined to maximize concentration. Each area should take no more than minutes to search. 2. Breaks should be taken after each search. (At least 10 minutes) 3. Search the same area twice so that nothing is overlooked

Legal Considerations Regarding Evidence Circumstances where the police can search for evidence in the absence of a search warrant: 1. Emergency circumstances 2. To prevent loss or destruction of evidence 3. A search of a person and property in immediate control of the person as long as it is in the event of a lawful arrest 4. A search made under consent of the party involved To avoid the exclusion of evidence in court, due to illegal search and seizure practices, the removal of any evidence from a crime scene must conform to Fourth Amendment privileges. In order to protect the rights of the people there must be probable cause before a specifically described site can be searched and items of evidence seized, under the authorization of a court issued search warrant

Purpose of an CSI examination is to: 1. Locate and identify potential evidence 2. Provide information about the crime or incident 3. Assist in the corroboration or otherwise of information provided by suspects, victims or witnesses

Type and Scale of Examination Determined by: 1. Seriousness of the offence/incident, type of the offence/incident and relevant circumstances 2. The nature of the scene

Before examining evidence, which involves moving, or disturbing it, the following should be checked: 1. Ensure appropriate OSHA requirements been followed (e.g. bio hazards procedures) 2. Has the area or item to be examined been photographed in place? 3. Ensure adequate notes, sketches and measurements of the area or item have been taken? 4. If the area or item is to be moved or disturbed during the examination, ensure that evidence will not be contaminated or destroyed?

Prioritize the collection of evidence to prevent loss of, or damage to, an item. Smaller items or evidence are usually prone to damage. Generally: Ensure fragile evidence is collected first e.g. latent fingerprints Then collect trace evidence e.g. blood and fiber Finally, collect larger items It may be better to collect too much than to overlook something important. Examination starts at the scene, however many items will require further examination under controlled conditions. Detailed records (written, sketched, photographic) should be maintained of all examinations and your findings. One of the most common crimes is that of break, enter and steal. Understanding how to examine this type of scene properly is essential. In many instances a break in (or scene made to look as if a break and enter took place) may be part of a more serious crime e.g. murder, sexual assault, arson.

Cross Contamination and Biological Degradation Prevent cross contamination and/or biological degradation. When collecting an item from the scene care must be taken to ensure that it is collected in a way, which will preserve (as closely as possible) its original condition.

Labeling At the time of collection: - a detailed label should be attached to the package and include all of the following: Time & date collected By whom collected Type of incident Description of the item Location of the incident Suspect & victims name if known Location of the item Name of the Senior CSI & their location CSIs – names and job number Labeling identifies the item, assists with proving continuity and ultimately admittance into evidence at court. Your organization will have standard procedures for labeling items.

Continuity is maintained by: Accurate records (of the scene and item) Detailed labeling, appropriate and sealed packaging Accurate official records and logs Secure storage of the item(s) Full documentation of any subsequent movement It is preferable that the CSI is the only link in the chain of custody of an item Continuity and Records Continuity refers to the chain of custody of an item, from initial location, collection and any subsequent movements of that item, through to admission into evidence at court. Where this is not possible, movement and handling of the item should be fully documented and kept to a minimum.

Interpretation may include: Assist in establishing how the incident occurred Prove or disprove witness, suspect or victims, versions of the incident Provide investigators with information, which may assist with inquiries and interviewing of witnesses, victims, and suspects With all aspects of searching, examining and collection undertaken, the most important aspects still remain, those of assessment and presentation of evidence. Assessment involves laying out all the known facts and piecing these together to reconstruct the events relative to the located physical evidence.

Suitable evidence is used in court. Interpretation may suggest a theory of what occurred, based on: Observations at the crime or incident scene The physical evidence located Information received from the Senior Investigating Officer e.g. interviews and subsequent inquiries Results of examinations, analyses and other specialized tests. Interpretation commences on your arrival at the crime or incident scene where you make an assessment based on the known facts and the physical evidence present. Interpretation is a way of thinking which focuses on the possible types of evidence which you might expect to find. It should not limit the examination but serve to enhance it. It is important to continually reassess your interpretation theory (s) as you process the scene (i.e. there may be several possible alternatives). Once the results of all the tests (e.g. physical comparison, experimental burn, blood groupings etc) are available then the crime scene investigator can formulate one or more interpretations of the scene from all available information.

The results of interpretation are the formation of opinions or likely conclusions Interpretation must be thorough and a reliable report made of the observations, rather than the investigator's belief of what occurred. Interpretation does not generally involve a total description of what occurred, but tends to be more specific in its purpose. Interpretation often defines the questions in contention and seeks to find possible answers. (e.g. the speed of a vehicle and position of the vehicles at the time of impact, in a vehicle collision.) Particularly in seeking expert opinions. The crime scene investigator should assess the likely worth or weight of expert opinions to the circumstances of the investigation. This should be discussed with the Senior Investigating Officer. The information, which the interpretation is based on The integrity of the physical evidence Who makes it? The circumstances of the incident.

4 Basic Limitations to the process of Reconstructing the incident: Quantity and quality of the information received, physical evidence present and method of recording. 2. Ability and expertise of the crime scene investigator. 3. Extent of interpretation required. 4. Time and financial resources available. 1. Facts may: Speak for themselves Require only the slightest inference Be scarce Be unreliable and therefore make interpretation difficult, inaccurate or poor recording of the crime or incident scene can render interpretation impossible

Human Remains and Identification Notes should include: Position of the body Description and state of clothing (is it partially removed, stained, tangled or twisted?) Describe the location, intensity, size, and direction of flow of any staining if possible. Type of stain (blood-like, semen, dirt, vomit, feces, urine or some other fluid) An investigator’s responsibility is to help establish the nature of death (accidental, homicide, suicide or natural causes) while preserving any evidence present at the scene. At a homicide scene, moving the body, clothing or any other items covering the corpse can easily result in the loss of evidence.

Any visible damage to the clothing and body Description of bloodstains (spots, spatter or smearing and directionality) Appearance of evidence removal (has the body been washed or blood cleaned from the body?) Estimated amounts of blood (has staining penetrated layers, carpeting or other surfaces, is it superficial?) Special consideration must be given if the corpse is located outdoors, or has apparently been moved from another location crime scene. The remains may be partially decomposed or damaged by insects or animals. The important points of processing human remains are stressed in an article that can be seen online at This paper stresses the need for careful examination and application of standard procedures for maximum crime scene and evidence protection and outlines the different types of evidence that may be encountered and include the appropriate techniques for the collection of Trace Evidence, Body Fluids and Latent prints

The Recovery Of Human Remains Outdoor vs. Indoor Decomposition Rates/Temp. 3.Use of Dogs to find bodies (9/11) A number of associated difficulties as often the body has undergone decomposition and alteration. There may be some skeletal parts and some organs remaining, which together with clothing fragments may provide useful evidence. Human remains are found in a variety of places; often outdoors, but also indoor, in attics, furnaces and basements. A body may have been buried in soil, frozen, covered with brush or overgrown vegetation. With outdoor remains, clothing and evidence may be spread over a wide area and have been subjected to animal interference and insect infestation.

Forensic Specialties Anthropology The scientific discipline mainly concerned with the study of bodily or skeletal remains. DNA, Mitochondrial DNA (family) Dr. Michael Baden/[ ]

Its possible to determine 2 types of information from remains: Physical characteristics such as sex, ethnicity, approximate age, stature, certain disease states and old injuries The actual identification of the individual Anthropologists can obtain information from teeth that may determine the approximate age of the victim. The cranium and the ossification lines, or sutures, of the cranium provide information on gender and approximate age. Approximate height can be determined from the skeleton and the longer bones of the limbs. Hair resists changes very well, if it hasn’t been exposed to fire and may still be found at the scene even when the body has undergone severe changes and decomposition. This may be used to determine the hair color of an individual.

Forensic Odontology Uses dental records to help in human identification, and is often necessary for the identification of unrecognizable bodies, after fires or mass disasters, and in the identification and comparison of bite marks.

Forensic Pathology Estimating Time of Death Changes in appearance of eyes Cooling of Body Temperature (livor mortis) Rigidity of the body (rigor mortis) Blood pooling in a specific area of the body (algor mortis) 5.Decomposition or putrefaction is the breakdown of the body due to autolysis and bacterial decomposition 6. Insect Infestation and Forensic Entomology In murder, accident, and suicide cases, establishing the time of death is important for the investigation. This can be done in a number of ways using post mortem changes. Changes in the eyes (dulling of the cornea and the appearance of a film) Body temperature cooling that can be related to the outdoor conditions ; temperature of the body at the time of death; whether the body is clothed or unclothed. A body usually reaches ambient temperature 18 to 20 hours after death Rigidity that appears 6 to 12 hours after death ( rigor mortis). The flaccid corpse begins to become rigid due to biochemical changes in the muscle tissue; the degree and extent of rigidity can be used to estimate time of death. Rigidity remains for 2 to 3 days then disappears again

Forensic Photography Crime scene photographs are permanent and comprehensive pieces of evidence that may be presented in court to prove or disprove facts in question. There are three things to record: The overview, a general shot with features to identify the location The location of any significant evidence, usually a mid-range shot The evidence detail, perhaps with close-up procedures If you are photographing injuries, then you must use color film and should be aware that injuries will change in appearance with time.

Blood Splatter Analysis -Bloodstain Interpretation Properly collected and preserved blood evidence can establish a link between an individual, a criminal act or a crime scene It is used to strengthen or contradict a witness or suspects statement or to eliminate a person as a potential suspect in a crime.

Blood Splatter Analysis Expert 1971 MacDonell (AFIP, Washington, DC) Outlined general rules regarding blood spatter evidence Outlined general rules of blood spatter pattern recognition including spot shape, edge characteristics, spot diameter, angle of impact, degree of spatter, directionality, cast off droplets and high and low velocity impact stains

Collecting Blood Evidence Collection and Preservation of Blood Evidence Dried Bloodstains Wet Bloodstains Luminol, an important, as this is one of the most useful agents in detecting minute quantities of blood, and can be used with the appropriate light source to locate blood in crevasses and minute traces where attempts have been made to clean up and conceal evidence.

Wet Blood Stains Liquid pools - pick up on gauze pad or other clean, sterile cotton cloth. Allowed to air dry thoroughly at room temp. Refrigerate or freeze as soon as possible. Delays beyond 48 hours may make blood samples useless. Deliver stained object immediately to lab. If the object must be mailed, allow the stain to air dry completely before packaging. Do not heat stained material or place it in bright sunlight to dry. Hang clothing and similar articles in a room where there is adequate ventilation. If not completely dry, label and roll in paper or place in a brown paper bag or box and seal and label container. Place only one item in each container. Do not use plastic containers.

Dried Blood Stains On clothing, wrap the item in clean paper, place the article in a brown paper bag or box and seal and label container. Small solid objects: send the whole stained object to the Lab. Large solid objects: cover the stained area with clean paper and seal the edges down with tape to prevent loss or contamination. If impractical to deliver the whole object to the Lab, scrape the stain onto a clean piece of paper, which can be folded and placed in an envelope. Scrape blood from objects using a freshly washed and dried knife or similar tool. Wash and dry the tool before each stain is scraped off. Seal and mark the envelope. Do not mix dried stains. Place each stain in a separate envelope. Do not attempt to wipe dried stains from an object using a moistened cloth or paper.

Motor Vehicle Investigation A vehicle, which may or may not be the primary scene, may need to be processed. A vehicle may be part of the investigation because it was stolen, used as a getaway vehicle or used for some other crime, and processing requires the same caution and detailed examination as any other crime scene. An investigator must take care to document all steps of the investigation, make a detailed inventory of property in the vehicle and obtain all fragile evidence first (such as fingerprints). The types of evidence present will vary depending on the circumstances and nature of the crime. For detailed evidence searching the vehicle should be towed, if possible, to a police compound or well-covered area and a systematic search for evidence conducted. Burglary of the vehicle may yield fingerprint evidence, whereas a vehicle used for a murder to transport a victim may hold an array of physical evidence.

Steps of Vehicle Processing Initial examination Written documentation of vehicle in original state Systematic photographic and documentation An organized section-by-section search should be conducted to find items of evidence not immediately obvious during the initial exam. Starting with the exterior, taken from each side, corners, front, rear, tag, including any decals, damage or custom accessories. The interior of the vehicle should be photographed from the front drivers area; from each side with the doors open, the ignition area, the dash, the glove box, the instrument panel, the rear seat area, and the trunk area

5. Other items of evidence located during the search should be annotated with evidence markers and photographed to record location and relationship of any evidence found 6. Collection of evidence, beginning with the most fragile evidence (trace evidence), evidence easily lost, or susceptible to damage or loss through handling or weather conditions

7. Mechanical processing for any latent fingerprints. 8. Control samples should be acquired, including glass samples, fiber samples for upholstery and carpet, chipped paint, and wiring for comparison with electronic components, like CD players and telephones that may have been stolen from the vehicle. Common sense areas should be searched around the sides, hood, trunk, roof support post, and windows of the exterior of the vehicle. Inside, the door handles, rear view mirror, seat belt buckles, windows, should also be searched

Abandoned Vehicles Types of Evidence to collect: Odometer readings Gas levels Appearance for reason for stopping there Damage Radiator temperature and ambient temperature to assist in determining the time of abandonment The site where the vehicle is found should be photographed and sketches should include details of distance to the closest inhabited house or town. Other points to note are:

Homicide - Vehicular Body located in car Body removed before car found In situations of terrorism or sabotage where the vehicle was destroyed by explosives, every attempt should be made to locate and collect all the pieces of the explosive device.

Hit and Run Investigations There are two types of scenes to process: Damage to other vehicles or property Death and injury

Types of vehicular physical evidence: Identity of the missing vehicle Connect the vehicle with the crime scene or the victim Help in reconstructing the events surrounding the crime

Known specimens from the hit and run vehicle Paint chips Headlight and tail lamp glass Bulb filaments Headlight lenses Signal reflectors Assoc. vehicle to crime Hairs Clothing fibers Paint Glass Blood Tissue

Vehicle Marks Tire impressions Wheel marks (used to determine the direction of vehicle movement) Skid marks (provide information on vehicle speed) Soil disturbances For more information on crash vehicle investigation see the TARO website at This site of the Traffic Accident Reconstruction Origin provides a number of crime scene scenarios for interpretation and discussion. These scenarios are based on actual cases.

Arrival at the Crime Scene
Upon arrival at a crime scene the 1st Responder police officer to a crime scene is responsible for: Acquiring medical assistance for injured victims Medical personnel avoid disturbing evidence and approach the victim by an indirect route. Detaining any potential suspects or witnesses Statements are taken from victims, witnesses, and suspects.

Arrival at the Crime Scene
3. Securing the crime scene to the greatest extent possible The boundary is sealed off, and guards are posted at the entry to the crime scene if needed. All civilians and unauthorized personnel are excluded from the crime scene. 4. Calling for any additional personnel needs such as other officers and/or forensic investigators. The personnel required depends upon the nature of the crime scene.

Securing the Crime Scene
The boundaries of the crime scene must be secured with crime scene tape, ropes, or cones. The secured area should include the area where the crime took place and the surrounding area where physical evidence may be located.

Securing the Crime Scene
Once the boundaries are secured, guards may be posted to restrict access to the crime scene. A detailed log is kept of personnel movements in and out of the crime scene. This log includes personnel names and time of entry or exit. Investigators should never do anything that might alter the crime scene including smoking, eating, drinking, or littering.

Surveying the Crime Scene
The Walkthrough – initial survey of the crime scene 1. Perpetrator’s point of entry and exit are located. 2. Indirect path is taken to the center of the crime scene. 3. Obvious items of evidence are located and documented. 4. The conditions of the scene are observed and recorded. Special attention is paid to item or conditions that suggest timing of the incident or do not appear to belong.

Primary Crime Scene --the location at which the initial crime occurred Ex: the house in which a murder occurred Secondary Crime Scene --the location at which events after the initial crime occurred Ex: the shallow grave in which a murder victim was buried Whether a crime scene is primary or secondary may be inferred by the presence or absence of specific evidence.

At the Command Center Investigators receive their assigned tasks from the lead investigator. Investigators store their equipment. Investigators meet to discuss aspects of the crime scene. Investigators and law enforcement personnel communicate with personnel at other crime scenes.

Searching the Crime Scene
The search for physical evidence at a crime scene must be thorough and systematic. The search pattern selected will normally depend on the size and locale of the scene and the number of collectors participating in the search. For a factual, unbiased reconstruction of the crime, the investigator, relying upon his or her training and experience, must not overlook any pertinent evidence. Physical evidence can be anything from massive objects to microscopic traces.

Searching the Crime Scene
Vehicle Searches -Investigators search interior and exterior of vehicle. -The vehicle may be searched at the crime scene or at the police department or crime laboratory garage. Night Searches -Investigators avoid carrying out outdoor or dark indoor crime scene searches at night. -If possible, the crime scene is secured and guarded until morning.

Crime Scene Evidence Forensic science begins at the crime scene.
If the investigator MUST recognize physical evidence or MUST properly preserve it for laboratory examination. NO sophisticated laboratory instrumentation or technical expertise can salvage a poorly investigated crime situation. It must be emphasized that the techniques of crime-scene investigation are not difficult to master and certainly lie within the bounds of comprehension of the average police officer.

Types of Physical Evidence
Blood, semen, and saliva Documents Drugs Explosives Fibers Fingerprints Firearms and ammunition Glass Hair Impressions Organs and physiological fluids Paint Petroleum products Plastic bags Plastic, rubber, and other polymers Powder residues Soil and minerals Tool marks Vehicle lights Wood and other vegetative matter

Procedures for Collection
Often, many items of evidence are clearly visible but others may be detected only through examination at the crime laboratory. For this reason, it is important to collect possible carriers of trace evidence, such as clothing, vacuum sweepings, and fingernail scrapings, in addition to more discernible items.

Procedures for Collection
Investigators must handle and process physical evidence in a way that prevents changes to the evidence through contamination, breakage, evaporation, accidental scratching or bending, or through improper or careless packaging. The use of latex gloves, disposable forceps, and sanitized equipment reduces the chance for contamination. Whenever possible, one should keep evidence in its original condition as found at the crime scene.

Packaging Each different item or similar items collected at different locations must be placed in separate containers. Packaging evidence separately prevents damage through contact and prevents cross-contamination. The well-prepared evidence collector will arrive at a crime scene with a large assortment of packaging materials and tools ready to encounter any type of situation.

Packaging Disposable forceps and similar tools may have to be used to pick up small items. Unbreakable plastic pill bottles with pressure lids are excellent containers for hairs, glass, fibers, and various other kinds of small or trace evidence. Alternatively, manila envelopes, screw-cap glass vials, or cardboard pillboxes are adequate containers for most trace evidence encountered at crime sites. Ordinary mailing envelopes should not be used as evidence containers because powders and fine particles will leak out of their corners.

Packaging Small amounts of trace evidence can also be conveniently packaged in a carefully folded paper, using what is known as a “druggist fold.” Evidence from arson scenes should be packaged in airtight metal or glass containers to prevent the loss of accelerant vapors.

Packaging If biological or bloodstained materials are stored in airtight containers, the accumulation of moisture may encourage the growth of mold, which can destroy the evidential value. In these instances, the material should be allowed to air-dry before being packaged in wrapping paper, manila envelopes, or paper bags.

Packaging Contamination is a key concern during the collection of DNA-containing specimens such as blood, saliva, sweat or skin cells. Contamination can occur either by introducing foreign DNA through coughing or sneezing onto evidence or if items of evidence are incorrectly placed in contact with each other during packaging. To prevent contamination, the evidence collector must wear a face mask and use disposable latex gloves and disposable forceps when collecting evidence that may contain DNA.

Chain of Custody Chain of Custody - a list of all persons who came into possession of an item of evidence. Continuity of possession, or the chain of custody, must be established whenever evidence is presented in court as an exhibit. Adherence to standard procedures in recording the location of evidence, marking it for identification, and properly completing evidence submission forms for laboratory analysis is critical to chain of custody. Every person who handled or examined the evidence and where it was at all times must be accounted for.

Obtaining Reference Samples
Standard/Reference Sample—Physical evidence whose origin is known, such as blood or hair from a suspect, that can be compared to crime-scene evidence. The examination of evidence, whether it is soil, blood, glass, hair, fibers, and so on, often requires comparison with a known standard/reference sample. Although most investigators have little difficulty recognizing and collecting relevant crime-scene evidence, few seem aware of the necessity and importance of providing the crime lab with a thorough sampling of standard/reference materials.

Submitting Evidence Evidence is usually submitted to the laboratory either by personal delivery or by mail shipment. Care must be taken in packaging evidence that will be sent by mail in order to prevent breakage or other accidental destruction during transit to the laboratory. Most laboratories require that an evidence submission form accompany all evidence submitted. Case information provided on this form enables the laboratory analyst to make an intelligent and complete examination of the evidence.

Crime Scene Safety Crime scenes frequently present the investigator with biological specimens of unknown origin; the investigator has no way of gauging what health hazards they may contain. Therefore, one must use caution and protection at all times. It is recommended by the International Association for Identification Safety Committee that crime scene personnel wear a minimum of latex gloves (double gloved) and protective shoe covers. In cases of large contamination areas, coveralls are also recommended.

Crime Scene Safety The use of a particle mask/respirator, goggles, or face shield is recommended in addition to the minimum protective items when potentially infectious dust or mist are present. Personnel should be alert to sharp objects, knives, hypodermic syringes, razor blades, and similar items. Personnel should maintain a red biohazard plastic bag for the disposal of contaminated gloves, clothing, masks, pencils, wrapping paper, and so on.

Search and Seizure Protocols
The removal of any evidence from a person or from the scene of a crime must be done in conformity with Fourth Amendment privileges: “The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizure, shall not be violated, and no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.”

Search and Seizure Protocols
The United States Supreme Court has determined that search and seizure without a court-approved warrant is justified in four cases: The existence of emergency circumstances The need to prevent the immediate loss or destruction of evidence A search of a person and property within the immediate control of the person provided it is made incident to a lawful arrest A search made by consent of the parties involved

Search and Seizure Landmark Cases
In the case of Mincey v. Arizona, the Court dealt with the legality of a four-day search at a homicide scene and determined that the evidence was illegally seized because a warrant was never issued and the circumstances of the case did not justify a warrantless search.

Search and Seizure Landmark Cases
In Michigan v. Tyler, fire destroyed a business establishment leased by Loren Tyler and a business partner. The court decided that evidence obtained from the initial search was legally seized, but evidence obtained from searches 4, 7, and 24 days after the incident were illegally seized.

Departing the Crime Scene
The experienced lead investigator decides when all pertinent physical evidence has been recorded and collected at the crime scene. A final survey is undertaken to visually review the scene and collect all evidence and equipment. Following the final survey, the crime scene is released to the proper authorities.

5 STEPS OF CRIME SCENE PROCESSING
1. Responding to the crime scene requires the CSI to arrive with a plan and the proper attitude. The CSI must communicate with the 1st Responding officers and learn as much as possible about what has taken place. Scene perimeters are established or enlarged and the scene is secured.

2. Crime scene photography is next. This step must be completed prior to moving or collecting any evidence. 3. Crime scene diagramming. The rough sketch with measurements must be completed prior to moving anything and a complete evidence list and sketch legend is completed.

4. Collection of physical evidence. The scene must be legally searched for evidence that is both seen and unseen. When evidence is found, it must be documented fully, collected properly and packaged in such a way to maintain its evidentiary value.

5. Processing the scene for fingerprints. Fingerprinting the crime scene is usually performed last because fingerprint powders will contaminate the scene. Those items or surfaces that need processing will have to be protected from contamination until after the scene has been processed. There are exceptions to this which are determined by the circumstances of each scene.

Processing a crime scene might take a few hours to several days. While processing the scene, you will have to make numerous decisions that will eventually be scrutinized by teams of lawyers and experts in various forensic disciplines. The lawyers and forensic experts have months and sometimes years to pull your work apart. Your work, based on your decisions, must be able to stand up to these numerous challenges.

CRIME SCENE DETECTIVE QUALITIES
3 qualities of a CSI: to be successful processing crime scenes: 1. Attitude - First, and most important, the crime scene detective must have the proper attitude or he/she will be defeated before starting. Crime scene work is very demanding both mentally and physically because the majority of evidence at major crime scenes is often hidden. Searching a scene for fingerprint evidence, trace evidence and processing a deceased body are extremely time consuming tasks and are often performed in confined spaces and awkward positions. It can be very easy to justify overlooking some of the processing techniques required for the successful recovery of evidence.

2. Training - The crime scene detective must continue to train. Training will provide the detective with guidance and the ability to better understand a crime scene. Training, however, is nothing without the proper attitude. The crime scene detective must be able to use the proper procedure at the proper time or the training was wasted.

3. Experience - The crime scene detective must have experience. Without experience, the detective may be overwhelmed at major crime scenes and evidence might be missed. The CSI should use property crimes such as burglaries to train for the more serious crimes against persons. The focus of a CSI should always be toward the homicide scene, the ultimate major crime.

Nothing can replace experience; however, continued training can prepare you to respond and react the way you have trained. IT ALL STARTS WITH YOUR ATTITUDE!

Crime Scene Notes Note taking begins when the investigator is contacted & requested to report to the crime scene. Crime scene notes should begin with: 1.The identity of person who contacted the investigator 2. Time of contact and arrival at the crime scene 3. Preliminary case information 4. Personnel present on arrival and those being contacted

Crime Scene Notes Notes contain a personnel log, all observations made by the investigator, and the time observations were made. Notes are taken in a uniform layout, concurrently as the observations are made. Notes are written in a bound notebook in blue or black ink.

Crime Scene Notes Investigators may choose to record crime scene notes on audio tapes. This leaves the hands free to process the scene as the notes are taken. Tape-recorded notes must eventually be transcribed to a written document.

Crime Scene Investigation

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