1. Seminar: Introduction to Forensic Science
Definition and Scope
Freddie Arocho-Perez
Kaplan University
SC155: Introduction to Chemistry

2. What is Forensic Science?
The application of science to those criminal and civil laws that are enforced by police agencies in a criminal justice system.
Any application of science to law enforcement.
Includes geology, chemistry, physics, biology, etc.
Criminalistics – any of the services provided by a crime laboratory.
For all intents and purposes, the term is interchangeable with forensic science.

3. Sir Arthur Conan Doyle Author of the Sherlock Holmes series.
Popularized forensic investigation through his novels.
Used up-and-coming detective methods in his stories, including fingerprinting, serology, firearm identification, and questioned documents.

4. Major Contributors to the Field
Mathieu Orfila ( ) – father of toxicology: the science of dealing with poisons and their effects.
Alphonse Bertillon ( ) – developed science of anthropometry – the taking of a series of body measurements for means of personal identification (later replaced by more reliable fingerprinting).
Francis Galton ( ) – first thorough study of fingerprints and how to classify them; offered statistical proof of their uniqueness.

5. Major Contributors to the Field
Edmond Locard ( ) – created the first rudimentary crime lab in Lyon, France (1910).
Locard’s Exchange Principle – when a criminal comes in contact with an object or person, a cross-transfer of evidence occurs.
"Every Contact Leaves a Trace"

6. Major Contributors to the Field
Every criminal can be connected to his/her crime scene by something as small as dust particles carried to or from the scene.
First to request that suspects’ clothing be examined in the lab.
His success led to the establishment of police labs in Vienna, Berlin, Sweden, Finland, and Holland.

7. FBI
Under director J. Edgar Hoover, national lab for forensic services established in 1932.
FBI lab is now the world’s largest, with 1 million examinations each year.

8. Introduction to Crime Scene Investigation
The purpose of crime scene investigation is to help establish what happened (crime scene reconstruction) and to identify the responsible person.
Carefully documenting the conditions at a crime scene and recognizing all relevant physical evidence.

9. Introduction to Crime Scene Investigation
The ability to recognize and properly collect physical evidence is oftentimes critical to both solving and prosecuting violent crimes.
It is important to determine the full extent of a crime scene.

11. The Crime Scene A place where a crime has taken place.
A starting point for a criminal investigation.
A crime scene is not merely the immediate area where a body is located or where an assailant concentrated his activities but can also encompass a vehicle and access/escape routes.

12. Crime Scene Vocabulary
Crime Scene: Any physical location in which a crime has occurred or is suspected of having occurred.
Primary Crime Scene: The original location of a crime or accident.
Secondary Crime Scene: An alternate location, such as where additional evidence may be found.
Suspect: Person thought to be capable of committing a crime.
Accomplice: Second person associated with committing a crime.
Alibi: Statement of where a suspect was at the time of a crime.

13. Types of Evidence
Evidence used to resolve a crime can be split into 2 areas: testimonial evidence and physical evidence.
The testimonial evidence would be any witnessed accounts of an incident or crime.
The physical evidence would refer to any material items that would be present on the crime scene or the victims. These items would be presented in a crime investigation to prove or disprove the facts of the issue.
Examples include DNA, the body itself, the weapon used, pieces of carpet, blood and other body fluids, fingerprints, or casts of footprints or tire prints.
Trace evidence refers evidence that is found at a crime scene in small but measurable amounts.

14. Crime Scene Search Patterns
The purpose of a search is to locate, identify, and collect any tangible material which may be associated with a suspect and/or victim from the crime scene and/or the crime.
There are standard search patterns used at a crime scene, especially when the scene is very large. These patterns include: spiral, grid, strip or line, and quadrant or zone search.

15. Investigating the Evidence
Forensic Science disciplines at the Illinois State Police Crime Labs
Investigating the Evidence
Drug Chemistry - Determines the presence of controlled substances and the identification of marijuana
Trace Chemistry - Identification and comparison of materials from fires, explosions, paints, and glass.
Microscopy - Identification and comparison of hairs, fibers, woods, soils, building materials, insulation and a broad group of materials referred to as "particulate unknowns.”
Biology/DNA - Presence and comparison of body fluids and dried stains such as blood, semen, and saliva.
Toxicology - Determines the presence of drugs and poisons in tissue, blood, urine and other body fluids.

16. Investigating the Evidence
Forensic Science disciplines at the Illinois State Police Crime Labs
Investigating the Evidence
Latent Prints - Identification and comparison of hidden impressions from sources like fingers, palms, feet, shoes, ears, lips or the tread on vehicle tires.
Firearms & Toolmarks - Examination and comparison of fired bullets, discharged cartridges, guns, gunpowder patterns, and marks left by erased serial numbers in metal or by burglary tools like a pry bar or screwdriver.
Questioned Documents - Side by side comparisons of questioned handwriting and hand printing, ink, paper, writing instruments, printers, photocopiers, additions, eradications, obliterations, watermarks, and impressions.

17. Analytical Instrumentation: HPLC
HPLC: High-Performance Liquid Chromatography
System is fully automated using data acquisition software.
HPLC is a commonly used technique for separating and analyzing sample components in the forensic laboratory.

18. HPLC Configuration

19. Analytical Instrumentation: HPLC

20. Evidence Examples Blood
There are 150 known proteins, 250 known enzymes, and many more antigens in blood.
Investigators can often estimate the time a crime occurred from how dry the blood is.
The shape of blood at the scene (pool, drops, stains, or splashes) can provides clues as to what happened as well as the location and description of bloodstains.
Blood evidence is frequently used to eliminate a pool of suspects.

21. Evidence Examples Wounds Tool Marks
Wounds can often be matched to weapons, tool marks on the weapon, or at least the weapon's size, shape, and length. 
Wound pattern analysis is a special technique that often provides clues to how a crime was committed or characteristics of the suspect (left-handed, right-handed, height, etc.).
Tool Marks
When a tool is made and used, tiny nicks and chips begin to form, which adds unique characteristics to its blade and edges. Tools may also pick up traces of substances it came in contact with.

22. Evidence Examples Skeletal Remains
Forensic anthropologists analyze skeletal remains to determine four characteristics for a victim: age, sex, race, and stature.
Determining the sex of a victim is the first step in the analysis of unidentified human remains. The innominate bone, which comprises the pelvis, offers the most definitive traits. The humerus or femur is also used and an analysis of the skull can give investigators clues about the whether the person was male or female.
Determining the age and stature (height) of a victim can be done by analyzing the development of the teeth, bone growth, and the length of specific bones, such as the femur.
Determining the race of a victim can be done by analyzing the skull for specific characteristics that are common among people of different races.

23. Evidence Examples Fingerprints Bite Marks
A fingerprint can conclusively identify both suspects and victims, since everyone has unique fingerprint patterns.
Databases, such as AFIS (Automated Fingerprint Identification System) are available for rapid computerized searching, on national, state and local levels.
Bite Marks
Each of the thirty-two teeth in humans is unique due to age and wear.
Bites can tell how quickly the offender subdued the victim and can often be matched to dental records.

24. Evidence Examples Facial Composites
Investigators work with sketch artists and eyewitnesses to create facial composites, or sketches of a person’s face.
Today many police departments are using facial reconstruction software to help them with this task.
The composite may be used internally to assist officers in identifying the suspect or used externally through local media (radio, TV, and newspaper) to solicit leads from citizens.

25. Evidence Examples Fluids
Semen, saliva or sweat can usually be found in spatters, drops or stains and can be fresh, coagulated or in dried form.
Each form has its own particular method of collection and preservation. 
Bodily fluids, such as vomit, can be found at scenes and used to test for alcohol, drugs, and poisons. Cigarette butts may contain dried saliva. Semen containing sperm is particularly valuable for DNA analysis.

26. Evidence Examples Paint
Paint is examined with microscopes and several analytic instruments to determine its chemical composition. There are forty thousand different types of paint classified in a database available to police. 
Paint can be transferred from one vehicle to another in an accident or a paint chip left at the crime scene can be used to determine the make and model of the vehicle it came from. Most paint evidence submitted to a lab will come from hit-and-run cases involving automobiles.

27. Evidence Examples Explosives
Powders and exploded/unexploded devices can be examined to determine what type of explosive may have been used.
After the Bomb Squad makes sure a device is safe, they submit a sample of the explosive or the debris to the Trace Unit. These items are then analyzed with chemical spot tests and analytical instrumentation to determine their chemical make-up to help identify which type of explosive was used.

28. Evidence Examples Glass
In car accidents, fragments of glass can be embedded in a victims’ hair or clothing. In break and entries, suspects often get glass fragments on their clothing.
Glass particles can be compared to particles collected from the crime scene to determine if they have a common origin.
Glass tint, thickness, UV fluorescence, density, and refractive index can all be used to match glass samples to glass found at a crime scene.

29. Evidence Examples Dust & Dirt Firearms (Ballistics)
This type of evidence can reveal where a person has been, where they live, where they work, and if they have pets.
Alibi soil samples are taken in many criminal investigations with most soil samples taken from the top surface of the soil in small amounts.
Firearms (Ballistics)
Characteristics of ammunition, components and residue are examined to find matches.
Bullets are never removed from their holes. The whole surrounding surface is cut out.

30. Crime Scene Protocol
Interview - The 1st step in processing a crime scene begins with interview of the first officer at the scene or the victim to determine what allegedly happened, what crime took place, and how was the crime committed. This information may not be factual information but it will give the investigators a place to start.
Examine - The 2nd step in the investigating a crime scene, which will help identify possible items of evidentiary nature, identify point of entry and point of exit, and getting the general layout of the crime scene.
Photograph - The 3rd step in the protocol, which involves creating a pictorial record of the scene and record items of possible evidence. Crime scene photographs are generally taken in two categories, overall views and items of evidence.

31. Crime Scene Protocol
Sketch - The 4th step in the protocol involves drawing a rough sketch to demonstrate the layout of the crime scene or to identify the exact position of the deceased victim or evidence within the crime scene. A crime scene sketch may not be completed on every case, however some form of sketching usually occurs in most cases, i.e., on a fingerprint lift card to identify exactly where the latent was recovered.
Process – This is the last step in the protocol. The crime scene technician will process the crime scene for evidence, both physical and testimonial evidence. It is the crime scene technicians responsibility to identify, evaluate and collect physical evidence from the crime scene for further analysis by a crime laboratory.

32. Processing the Crime Scene
There are 7 steps to processing a crime scene:
Secure and Isolate the Crime Scene
Record the Scene Photograph, Sketch, Take Notes
Conduct a Systematic Search For Evidence
Collect and Package Evidence
Maintain Chain of Custody
Obtain Controls
Submit Evidence to the Laboratory

33. Crime Scene Investigation Team
Team Leader
Photographer and Photographic Log Recorder
Sketch Preparer
Evidence Recorder/Evidence Recovery Personnel
Specialists

34. Crime Scene Search Patterns
Important things to do during a search:
Search from the general to the specific for evidence.
Be alert for all evidence.
Search entrances and exits.
Discuss the search with all personnel.

35. Recording the Crime Scene
Documentation includes transient details such as lighting (on/off), drapes (open/closed), weather, or furniture moved by medical teams.
The scope extends to possible arguments which might be made in this case (suicide/self defense) and documenting conditions supporting or refuting these arguments.

36. Recording the Crime Scene
Important to recognize what should be present at a scene but is not (victim's vehicle or wallet) and objects which appear to be out of place (ski mask) and might have been left by the assailant.

37. Photographing the Crime Scene
Photograph entire area before it is entered.
Photograph victims, crowd, and vehicles.
Photograph entire scene with overall, medium and close-up coverage, using measurement scale when appropriate.
Photograph major evidence items before they are moved.
Photograph all latent fingerprints and other impression evidence before lifting and casting are accomplished.
Prepare photographic log and sketch.

38. Sketching the Crime Scene
Documentation of physical evidence locations, as well as measurements showing pertinent size and distance relationships in the crime scene area.

39. Collecting Physical Evidence
Any collected evidence should have its location and condition documented before it is removed.
Describe evidence and its location on appropriate bag or envelope.
Evidence should be collected in appropriate containers, wearing gloves.

40. Collecting Physical Evidence
Containers/envelopes should be sealed with tamper-proof tape.
Seals should be signed.
Chain of Custody must be maintained:
Sign/date evidence container.
Maintain evidence log.

41. Obtaining Controls from the Crime Scene
Controls are physical evidence whose origins are known, such as carpet fibers from a suspects home, that can be compared to crime scene evidence.
The crime lab must have a thorough sample of control materials for comparison.

42. Submitting Evidence to the Crime Lab
Evidence can be submitted to the crime laboratory by a crime scene investigator personally or via the mail
Chain of Custody must be maintained at all times
Many labs require specific documentation before they will process evidence
Evidence evaluated by the lab may take a long time to process, or be held due to back log.

43. Identification of Illicit Drugs
Drug evidence can be collected in the form of:
Powders
Tablets
Capsules
Vegetable matter
Liquids
Pipes
Cigarettes
Cookers
Syringes
They contain active drug ingredients as well as inactive substances or additives (sugar, starch, quinine) to increase quantity, dilute potency, and raise total value.

44. Classes of Drugs Narcotics: Hallucinogens:
analgesics, relieve pain by depressing central nervous system activity;
leads to physical dependence;
opium derivatives, such as morphine, heroin
Hallucinogens:
Cause marked changes in thought processes, perceptions, and mood
Includes marijuana, LSD, PCP, MDMA

45. Classes of Drugs Depressants: Stimulants:
Alcohol, barbiturates, tranquilizers, inhalants
Stimulants:
Amphetamines, cocaine, crack

46. 2-Step Procedure:
1) Use screening tests to reduce the number of possibilities to a small and manageable number.
2) Use more sophisticated tests to pinpoint and confirm the identity of the drug.

47. Illicit Drugs – Color Tests
Color tests: not conclusive evidence – presumptive test only.
Marquis test: 2% formaldehyde in sulfuric acid – turns purple in the presence of heroin, morphine, and other opium derivatives.
Duquenois-Levine test:
Solution A – 2% vanillin and 1% acetylaldehyde in ethyl alcohol
Solution B – concentrated HCl
Solution C – chloroform
Purple color in the chloroform layer indicates marijuana

48. Illicit Drugs – Color Tests
Van Urk test:
1%p-dimethylaminobenzaldehyde in 10% conc. HCl and ethyl alcohol
Turns blue-purple in presence of LSD
Difficult to perform in the field because of small batches of LSD produced
Scott test:
Solution A – 2% cobalt thiocyanate in 1:1 water and glycerine
Solution B – conc. HCl
Solution C – chloroform
Test for cocaine

49. Sophisticated Tests for Drugs
Microcrystalline tests:
Chemical reagent is added to drug sample on a microscope slide
A chemical reaction happens, forming a crystalline precipitate on the slide
The sizes and shapes of the crystals are specific to a particular type of drug.

50. Sophisticated Tests for Drugs
Chromatography:
Thin-layer and gas chromatography separate drugs from their diluents
Requires a comparison between known and unknown drugs, so one must have a tentative ID before using.
Complements the color and crystal tests.

51. Sophisticated Tests for Drugs
Spectrophotometry:
Measures the absorption of light in the ultraviolet (UV) and infrared (IR) regions of the electromagnetic spectrum.
UV is not conclusive; establishes probable identity only
IR can specifically identify a substance, like a fingerprint

52. Sophisticated Tests for Drugs
Mass spectrometry:
Sample is exposed to high-energy electrons to break the sample molecules – no two compounds fragment in exactly the same way
Used in conjunction with gas chromatography (GC/MS)