2. Crime Investigation & Forensic Science By Muhammad Tariq Chohan

3. Sequence Introduction Definition of crime
Investigation – concept and tools
Kind of evidence
Forensic Science - definition and concept
Basic principles of Forensic Science
Applications: Anthropometry, dactylography, DNA ,
blood sampling, document analysis
Problems and limitations
Conclusion

4. Introduction A

5. Definition of Crime
A Crime is the commission or omission of any act, which is prohibited or required by the penal code of an organized political state, to which some punishment or sanction is attached.

6. Classification
Crime against person e.g Murder, Attempted Murder, Hurt, threats etc.
Crime against property e.g Dacoity, Robbery, theft, House breaking, extraction etc.
Fraud and forgery e.g fake documents, embezzlement etc.
Cyber Crime

7. Crime Investigation
Definition:- An investigation is systematic, minute and thorough attempt to
learned the facts about some thing complex or hidden
Police Investigation - the investigation of criminal activities
Investigating, investigation – the work of inquiring into something thoroughly
and systematically
Detecting, detective work, sleuthing, detection – a police investigation to
determine the perpetrator; “ detection is hard on the feet”
Forensics – Scientific tests or techniques used in the investigation of crimes
Roundup – the systematic gathering up of suspects by the police; “ a mass
roundup of suspects”
Surveillance – close observation of a person or group ( usually by the police)

8. Investigator Someone who gathers, documents and evaluates evidence.
Strong professional training and experience
Strong degree of self-discipline
Uses legally approved & ethical methods
Strong people skills
Includes all evidence of innocence as well as guilt
Uses systematic methods of inquiry
Uses both inductive and deductive reasoning
Compassionate, not calloused and cynical
Has wide ranging contacts across many occupations
Remains objective at all times
Leaves nothing to chance during investigation

9. Investigative Process
Objectives
Establish if a crime was committed
Collect, document and preserve evidence
Identify and apprehend the suspect(s)
Recover stolen property
Assist in the prosecution of the person(s) charged with the crime(s)

10. Location where the offense was committed
Crime Scene
Location where the offense was committed
May include surrounding areas where evidence may
be located
Always start big It’s much easier to make it smaller
than to expand it at a later time
There may be more than one crime scene
Macroscopic versus Microscopic scenes

11. Keep known fact AND inferences in mind when processing scene
CONCEPTUALIZATION
Keep known fact AND inferences in mind when processing scene
Facilitates reconstruction of the offense
Identification of the modus operandi
Identification of certain types of evidence
Assists in establishing investigative direction

12. CRIME SCENE SEARCH PATTERNS
Spiral
Strip/Line
Grid
Zone/Quadrant
Pie/Wheel
The crime scene coordinator may choose from a variety of crime scene search patterns based upon the type and size of the crime scene.

13. WAYS TO DOCUMENT A CRIME SCENE VISUALLY INCLUDE: Video taping
DOCUMENTATION
Constant Activity
Starts with rough shorthand field notes
Sketches
Diagrams to scale
WAYS TO DOCUMENT A CRIME SCENE VISUALLY
INCLUDE:
Video taping
Photographing
Sketching

14. Categories of Evidence
Corpus Delicti evidence
Evidence that helps to prove the elements of the crime(s)
Associative evidence
Evidence that connects the suspect to the scene and/or victim or connects the scene/victim to the suspect
It is bidirectional
Trace evidence
Small or microscopic evidence, or evidence in limited amounts

15. Forensic Science - definition and concept
Forensic science (often shortened to forensics) is the application of a broad spectrum of sciences to answer questions of interest to a legal system. This may be in relation to a crime or a civil action.
Forensic Science is concerned with reconstruction of unique events – attempting to determine what happened, how it happened, where and when it happened, and who was involved.

16. Five stages of physical evidence of process
Foundation
Recovery
Analysis
Interpretation
Presentation

17. Principles of Forensics Science
1.Principles concerning occurrence of evidence
Locard principles of exchange: “ Every contact leaves a trace”.
The dust and debris that cover our clothing and bodies are the mute witnesses, sure and faithful, of all our movements and all our encounters.
The absence of evidence is not necessarily the evidence of absence.

18. Cont…. 2. Principles of evidence recovery First, do no harm
Nothing should be added
Nothing should be damage
Nothing should be lost

19. Cont…. 3. Principles of analysis Scientific method Observation
Data collection
Conjecture / hypothesis
Testing results
Theory

20. Cont… 4. Principles of interpretation
Principle of individuality. Tow objects may be indistinguishable but no tow objects are identical
Principle of comparison: tow objects are said to match ( be indistinguishable) when there are no unexplained, forensically significant differences between them

21. 5- Principles of presentation Working within an ethical framework, a forensic scientist should fully disclose and present impartial evidence which is readily under stanadable and neither overstated nor understated.

22. ANTHROPOMETRY
First method of criminal identification thought to be reliable; based on a criteria of body measurements
Developed by Bertillon ( )/father of criminal identification
After 1883 the system was adopted throughout Europe
System was abandoned because dactylography (fingerprint identification) simpler, more reliable

23. HENRY BERTILLON AND A BERTILLON MEASUREMENT

24. MILESTONES IN THE DEVELOPMENT OF DACTYLOGRAPHY
1684 England’s Dr. Grew observes pores and ridges in hands and feet
1823 Perkinje develops nine standard fingerprint patterns and classification system
1892 Galton publishes “Fingerprints,” first definitive book on dactylography
1894 Vucetich publishes “Dictiloscopia Comparada”, outlining his system

25. MILESTONES IN THE DEVELOPMENT OF DACTYLOGRAPHY (Cont.)
1900 The Henry system was adopted in England
1901 Henry publishes “Classification and Use of Fingerprints,” outlining his system of fingerprint classification
1903 The Will West/William West case demonstrates the superiority of dactylography to anthropometry

26. THREE BROAD CATEGORIES OF LATENT FINGERPRINTS
Plastic prints
Created when the fingers touch against some material such as putty
Contaminated/visible prints
Formed when the fingers are contaminated with such things as ink or blood and touch a clean surface
Latent/invisible prints
Left on a surface from the small amounts of body oil and perspiration that are normally found on friction ridges
3-9(a)

27. CONDITIONS AFFECTING THE QUALITY OF LATENT FINGERPRINTS
The surface on which the print is deposited
The nature of the material contaminating the fingerprint
Any physical or occupational defects of the person making the print
How the object on which the prints appear was handled
The amount of the contamination
3-10

28. METHODS OF DEVELOPING LATENT PRINTS
Traditional powders
Fluorescent Powders
Chemicals
Cyanoacrylate of superglue fuming
Visualization under:
Laser
Alternative light
Ultraviolet illumination
3-11

29. LOCATING PRINTS Crime Scene Technician
This technician is using powder to develop latent prints
Technicians often wear protective equipment
Several points can be seen
(Courtesy Nassau County, New York, Police Department)
3-12

30. PORTABLE SUPERGLUE FUMING CHAMBER
is used to process the inside and the outside of the car.
is more efficient for processing larger objects.

31. LOCATING AND HANDLING SOIL EVIDENCE
Soil evidence is important when the suspect drives/walks on unpaved areas
It is picked up by:
tire treads
shoe bottoms
pants cuffs
It may also be located in:
subject's vehicle
articles in a suspect's trunk
3-4

32. PRESERVING FOOTWEAR AND TIRE PRINTS AND IMPRESSIONS
Footwear prints and impressions should be photographed:
As part of the general scene
Also photograph with a scale
Dental Stone is used in casting impressions
3-5

33. FOOTWEAR IMPRESSIONS
Photographs of footwear impressions at a crime scene
In the first photo only the impressions are shown
In a subsequent photo a ruler will be added to show sizes
Later casts will be made of the impressions
(Courtesy Tampa, Florida, Police Department)
3-6

34. collecting glass and paint evidence
Paint may be collected from the suspect's tools or clothing.
Paint can often be collected in dried chips.
Glass is a common form of evidence at burglary scenes.
Before any glass fragments are removed from a glass window it should be photographed.
3-7

35. DNA
Deoxyribonucleic Acid, chemical blueprint which determines everything from our hair color to our disease vulnerabilities; with the exception of identical twins, each person has a unique DNA makeup
DNA is unique to individuals
The human sources of DNA are: blood and tissue; spermatozoa; bone marrow, tooth pulp and hair root cells

36. DNA TYPING DNA is a chemical blueprint
The Enderby cases were the first use DNA typing in England in 1987
The Orlando cases were the first used in the U.S. in1986
The FBI crime lab was the first public lab to use DNA analysis in 1988

37. SOURCES OF DNA EVIDENCE
These are common sources of blood and DNA evidence that investigators need to be aware of in conducting crime scene searches.
Evidence
Possible Location of DNA on the Evidence
Source of DNA
Baseball bat or similar weapon
Hat, bandana, or mask
Eyeglasses
Facial tissue or cotton swab
Dirty laundry
Toothpick
Used cigarette
Stamp or envelope
Tape or ligature
Bottle, can, or glass
Used condom
Blanket, pillow, or sheet
“Through and through” bullet
Bite mark
Fingernail or partial fingernail
Handle, end
Inside
Nose or ear pieces, lens
Surface area
Tips
Cigarette butt
Licked area
Inside or outside surface
Sides, mouthpiece
Outside surface
Person’s skin or clothing
Scrapings
Sweat, skin, blood, tissue
Sweat, hair, dandruff
Sweat, skin
Mucus, blood, sweat, semen, earwax
Blood, sweat, semen, vomit
Saliva
Skin, sweat
Saliva, sweat
Semen, vaginal or rectal cells
Sweat, hair, semen, urine, saliva, dandruff
Blood, tissue
Blood, tissue, sweat

38. IDENTIFYING AND ANALYZING BLOOD STAINS
If blood at the crime scene is fresh and relatively uncontaminated, identification is not difficult
If the conditions at a crime scene are otherwise it is more difficult to identify
One preliminary field test involves the use of Hemident
Blood analyses is important because of the value of DNA typing
3-16

39. HEMIDENT
The use of Hemident in a presumptive or preliminary field test for blood.
(Courtesy Lightning Powder Company, Salem, Oregon)
3-18

40. FORENSIC DENTISTRY
Forensic dentistry is a specialty that relates dental evidence to investigation
Analyses of bit marks had played a major role in many cases
Teeth marks may be left in food, pencils or other items left at crime scenes
Bite marks can help eliminate or identify suspects

41. DENTAL COMPARISON
Dental records are very useful in helping to identify unknown persons who have been the victim of fowl play or who have been reported simply missing.
(Courtesy Dr. Richard R. Souviron, D.D.S., ABFO, Chief Forensic Odontologist, Dade County Medical Examiner Department, Miami, Florida)
3-15

42. MILESTONES IN FIREARMS IDENTIFICATION
1835 Henry Goddard
First successful murderer identification from bullet removed from victim’s body
1889 Professor Lacassagne identified grooves on a removed bullet removed from a corpse and matched it to a suspect’s weapon
1898 Jeserich took microphotographs of fatal and test bullets
He testified the defendant’s revolver fired the fatal bullet
1926 Calvin Goddard was most responsible for raising firearm identification to a science

43. BULLET IDENTIFICATION
When a bullet passes through the barrel of a weapon distinctive scratches are caused
These scratches can be compared to bullets fired through firearms in question
Identification is affected by the condition of the gun and of the bullets
3-20

44. TECHNIQUES FOR IDENTIFYING QUESTIONED DOCUMENTS
Handwriting and handprinting examinations
There are three types of forgery:
Traced forgery
Simulated forgery
Freehand forgery
3-22(a)

45. TECHNIQUES FOR IDENTIFYING QUESTIONED DOCUMENTS (cont'd)
Photocopier examination
Paper examination
Age of documents
Burned or charred paper
Altered or obliterated writing
Writing instruments
mechanical-impression instruments
Typewriting
3-22(b)