1. Forensic Science A diverse and incredibly broad
Includes chemistry, geology, biology, physics, and computer technology

2. Forensics
Application of science to criminal and civil laws that are enforced by police agencies in a criminal justice system
American Academy of Forensic Science
Criminalistics
Physical Anthropology
Engineering Science
Psychiatry and Behavioral Science
General
Jurisprudence
Questioned Documents
Odontology
Toxicology
Pathology/Biology

3. Major Players Mathieu Orfilia – father of forensic toxicology
Alphonse Bertillon – first systematic system of personal identification
Francis Galton – first study & classification of fingerprints
Leone Lattes – procedure to determine blood type from dried bloodstains
Calvin Goddard – used a microscope to compare bullets (determine if a particular gun fired the bullet)

4. Major Players
Albert Osborn – developed the principles of document examination
Hans Gross – wrote the first treatise describing the application of scientific principles to the field of criminal investigation
Edmond Locard – incorporated Gross’ principles into the first crime laboratory
Sir Alec Jeffreys – developed the first DNA profiling test in 1984

5. Important Developments
Earliest record of applying forensics to solve criminal cases comes from 3rd century China
Advances in science during the mid 1800s (microscope, photography)
Sherlock Holmes (19th Century) - Applied the newly developing principles of serology, fingerprinting, firearms identification, and questioned-documents examination
Computer technology (20th Century) has advanced the analysis of evidence; computerized databases

6. Forensic Science
A very small percentage of police investigations necessitate scientific examination
Yet the past 40 years have seen an astonishing growth in crime labs
Drug-Related Arrests
DNA Profiling

7. Forensic Scientists 3 Main Responsibilities of the Forensic Scientist
To collect and analyze the evidence in a criminal investigation
applying the principles and techniques of the physical and natural sciences
To provide expert witness testimony
To participate in the training of law enforcement personnel in the proper recognition, collection, and preservation of physical evidence

8. Analyzing Physical Evidence
Only physical evidence is free of inherent error or bias
Therefore, it must undergo scientific inquiry and follow strict guidelines that ensure the integrity of the information derived
Admissibility of Evidence
Testimony is based on sufficient data/facts
Evidence a product of reliable principles & methods
Principles & methods have been applied reliably to the facts of the case

9. Expert Witness
An expert witness is an individual whom the court determines possesses skill or knowledge relevant to the trial that is not expected of the average person.
Knowledge/skill may be acquired through experience, training, education, or a combination
Just as important as knowledge, are demeanor and ability to explain data and conclusions clearly, concisely, and logically
Called upon to evaluate evidence based on specialized training and experience that the court lacks the expertise to do
The expert will then express an opinion as to the significance of the findings; only one allowed to do so

10. Sketch or describe what you perceive a typical crime lab to look like
The Crime Lab
Sketch or describe what you perceive
a typical crime lab to look like

11. Crime Laboratories
Oldest forensic lab in the US is that of the LA Police Dept, created in 1923
FBI organized a national laboratory that offers forensic services to all law enforcement agencies in the country
The US has no national system of forensic laboratories (like the UK does)

12. Crime Laboratories
Size and diversity of crime labs make it impossible to describe a “typical” one
Operate as a part of a police dept
Operate under the protection of a prosecutor or DA
Work with the medical examiner or coroner
Associated with universities
Act as completely separate private entities

13. Forensic Databases
The Integrated Automated Fingerprint Identification System (IAFIS), a national fingerprint and criminal history system maintained by the FBI.
The Combined DNA Index System (CODIS) enables federal, state, and local crime laboratories to electronically exchange and compare DNA profiles.
The National Integrated Ballistics Information Network (NIBIN) allows firearm analysts to acquire, digitize, and compare markings made by a firearm on bullets and cartridge casings.
The International Forensic Automotive Paint Data Query (PDQ) database contains chemical and color information pertaining to original automotive paints.
SICAR (shoeprint image capture and retrieval) is a shoeprint database.

14. Physical Evidence
Any object that can establish that a crime has been committed or can link a crime and its victim or perpetrator
Physical Evidence is only useful if it is first recognized as evidence

15. Physical Evidence Almost anything can be Physical Evidence.
It would be impossible to list all the objects that could conceivably be of importance to a crime.
Why is it so important to be able to recognize physical evidence?
So that it can be collected and analyzed.
The importance a given piece of evidence will have in a case cannot be predetermined – the weight given will be decided by a jury

16. Common Types of Physical Evidence
Blood, Semen, Saliva
Paint
Documents
Petroleum products
Drugs
Plastic bags
Explosives
Plastic, rubber, & other polymers
Fibers
Powder residues
Fingerprints
Serial numbers
Firearms & ammunition
Soil & minerals
Glass
Tool marks
Hair
Vehicle lights
Impressions
Wood & other vegetative matter
Organs & physiological fluids

17. Value of Physical Evidence
Lies in its ability to corroborate events with data in a manner that is, as nearly as possible, free of human error and bias
As the number of different objects linking an individual to a crime scene increases, so does the likelihood or probability of that individual’s involvement with the crime
A person may be exonerated or excluded from suspicion of physical evidence collected at a crime scene is found to be different from standard/references samples collected

18. Limits to Physical Evidence
Natural Variation – modern analytical techniques have become so sensitive that natural variations in objects have become almost infinite – no 2 things are alike in every detail
Evidential Variations – are not the same as natural variations – distinguishing variations of evidential use from natural variations is not always an easy task.

19. CSI Effect What is the CSI Effect?
How do you think it has affected the way forensic scientists operate?
Compare and contrast the effect Sherlock Holmes had on forensics in the 1800s to that of CSI-type shows today.

20. Searching for Evidence
Must be thorough and systematic
Why?
The investigator must not overlook any pertinent evidence
How?
The search pattern will depend on
the size and locale of the scene and
the number of collectors participating in the search
the actions of the suspect(s) and victim(s) at the scene

21. Searching the Crime Scene
Physical evidence can be anything from massive objects to microscopic traces
It is important to collect possible carriers of trace evidence, such as clothing, vacuum sweepings, and fingernail scrapings, in addition to more discernible items
Often, many items of evidence are clearly visible but others may be detected only through examination at the crime laboratory

22. Figure 2–7 Several typical examples of crime-scene search patterns
Figure 2–7  Several typical examples of crime-scene search patterns. The pattern selected normally depends on the size and locale of the scene and the number of collectors participating in the search.

23. Packaging Physical Evidence
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

24. Packaging Physical Evidence
A 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
Forceps and similar tools – used to pick up small items
Unbreakable plastic pill bottles with pressure lids – excellent containers for hairs, glass, fibers, and various other kinds of small or trace evidence
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

25. Packaging Physical Evidence
Small amounts of trace evidence can also be conveniently packaged in a carefully folded paper, using what is known as a “druggist fold.”
Taking a sheet of paper fold 1/3
Fold the other side 1/3
Turn 90 degrees and Fold 1/3
Fold 1/3 again

26. Packaging Physical Evidence
Although pill bottles, vials, pillboxes, or manila envelopes are good universal containers for most trace evidence, two frequent finds at crime scenes warrant special attention.
Bloodstained materials
If stored in airtight containers, the accumulation of moisture may encourage the growth of mold, which can destroy the evidential value of blood.
In these instances, wrapping paper, manila envelopes, or paper bags are recommended packaging materials.
Charred debris
Must be sealed in airtight containers to prevent evaporation of residues

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

28. Standard/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.
Why?
The examination of evidence, whether it is soil, blood, glass, hair, fibers, and so on, often requires comparison with a known standard/reference sample.
Most investigators can recognize and collect relevant crime-scene evidence
However, few seem aware of the necessity and importance of providing the crime lab with a thorough sampling of standard/reference materials.

29. Submitting Evidence
Submitted to the laboratory either by personal delivery (courier) or by mail shipment
Method determined by distance the submitting agency must travel to the lab and the urgency of the case
Evidence Submission Form must accompany all evidence submitted

30. Evidence Submission Form
Enable laboratory analyst to make an intelligent and complete examination of the evidence
Brief description of case history
Particular kind of examination requested for each type of evidence
List of items submitted for examination
Each item must be packaged separately and assigned a number or letter

31. Analyzing Physical Evidence
Identification vs Comparison
Individual vs Class Characteristics

32. Identification
The process of determining a substance’s physical or chemical identity with near absolute certainty as existing analytical techniques will permit
Adoption of testing procedures that give characteristic results for specific standard materials
Once established, they may be permanently recorded and used repeatedly to prove the identity of suspect materials
Requires that the number and type of tests needed to identify a substance be sufficient to exclude all other substances

33. Comparison Two step process
The process of ascertaining whether two or more objects have a common origin
Subjects a suspect specimen and standard/reference sample to same tests
Two step process
Combinations of select properties are chosen from the suspect and standard/reference specimen for comparison
Forensic scientist must draw conclusions about the origins of the specimens

34. Individual Characteristics
Properties of evidence that can be attributed to a common source with an extremely high degree of certainty
In all cases, it is not possible to state with mathematical exactness the probability that the specimens are of common origin.
It can only be concluded that this probability is so high as to defy mathematical calculations or human comprehension.

35. Class Characteristics
Properties of evidence that can be associated only with a group and never a single source
Surprising to the inexperienced forensic scientist is the frequent inability of the laboratory to relate physical evidence to a common origin with a high degree of certainty
Here again, probability is a determining factor.
Nevertheless, the high diversity of class evidence in our environment makes their comparison very significant in the context of a criminal investigation.

36. Class Characteristics
Most items of physical evidence retrieved at crime scenes cannot be linked definitively to a single person or object
The value of class physical evidence lies in its ability to provide corroboration of events with data that are, as nearly as possible, free of human error and bias.

37. Individual or Class?
the matching ridge characteristics of two fingerprints
the comparison of random striation markings on bullets or tool marks
the comparison of two single-layer automobile paint chips of a similar color
the comparison of irregular and random wear patterns in tire or footwear impressions
the comparison of two blood specimens for blood type
the comparison of handwriting characteristics
the fitting together of the irregular edges of broken objects in the manner of a jigsaw puzzle
matching sequentially made plastic bags by striation marks running across the bags

38. Reconstruction
The method used to support a likely sequence of events at a crime scene by observing and evaluating physical evidence and statements made by those involved with the incident
Relies on the combined efforts of medical examiners, criminalists, and law enforcement personnel to recover physical evidence and to sort out the events surrounding the occurrence of a crime

39. Reconstruction
Physical evidence left behind at a crime scene plays a crucial role in reconstructing the events that took place surrounding the crime.
The evidence alone does not describe everything that happened
It can support or contradict accounts given by witnesses and/or suspects.
Information obtained from physical evidence can also generate leads and confirm the reconstruction of a crime to a jury

40. The Crime Scene

41. Securing the Scene Who? How? Why? First officer on the scene
First priority is medical assistance
Exclude all unauthorized personnel
Put up ropes/barricades
Why?
Every individual who enters the scene has the potential to destroy physical evidence

42. Lead Investigator Determines boundaries of the scene
Establishes path of entry/exit
Document & photograph evidence
Walk-through to gain overview & develop strategy to systematically examine & document the entire scene

43. Recording the Scene Why? How?
Investigators only have a limited amount of time to work a crime site in its untouched state
How?
Photography
Sketches
Notes

44. Photography Must be photographed as completely as possible Include
Area in which the crime actually took place
All areas adjacent to the crime
Overview photographs
From all angles

45. Photography
All items of physical evidence must be photographed to show their position and location relative to the crime scene
Videotaping crime scenes
Long shots
Close ups
Narration

50. Sketches Initial sketch need not be polished
Rough Sketch – drawn at the crime scene that contains an accurate depiction of the dimensions of the scene and shows the location of all objects having a bearing on the case
Finished Sketch – a precise rendering of the crime scene, drawn to scale

51. Rough Sketch Shows All recovered items of physical evidence
Important features of the crime scene
Accurate distances (measurements taken with a tape measure)
Legend or list that correlates letters to an item’s description
Compass heading showing North

52. Figure 2–4 Rough-sketch diagram of a crime scene
Figure 2–4  Rough-sketch diagram of a crime scene. Courtesy Sirchie Finger Print Laboratories, Inc., Youngsville, N.C.,

53. Finished Sketch
Must reflect information contained within the rough sketch in order to be admissible evidence in a courtroom
CAD (computer aided drafting) has become the standard method of constructing crime scenes from rough sketches

54. Figure 2–5 Finished-sketch diagram of a crime scene
Figure 2–5  Finished-sketch diagram of a crime scene. Courtesy Sirchie Finger Print Laboratories, Inc., Youngsville, N.C.,

57. Note:
Actual objects are not drawn in, rather a legend is used to indicate position

62. Notes
Note taking must be a constant activity throughout the whole processing of the crime scene
Must also be extremely detailed
Include
Detailed description of the scene
Location of items of physical evidence
Identify the time an item was discovered, by whom, how, and by whom it was packaged and marked
The disposition of the item after it was collected

65. Beyond the Crime Scene
Medical Examiner or Coroner will examine the victim
To search for physical evidence
To establish cause and manner of death
Collect tissues and organs for toxicology and pathology examinations.
Arrangements must also be made between the examiner and investigator to secure items taken from the body for closer laboratory examination.

66. Beyond the Crime Scene
The following are to be collected and sent to the forensic laboratory by the pathologist:
Victim’s clothing
Fingernail scrapings
Head and pubic hairs
Blood (for DNA typing purposes)
Vaginal, anal, and oral swabs (in sex-related crimes)
Recovered bullets from the body
Hand swabs from shooting victims (for gunshot residue analysis)