Intro to Forensic Scienceand

Crime Laboratories

2014-2015

What is Forensic Science?

• Forensic Science is the study and application of science to matters of the law.

• The term CRIMINILISTICS can be used synonymously with FORENSIC SCIENCE– Interchangeable (same meaning)

3 Major Avenues Available to Police Investigators in Solving a Crime

• Confessions• Some suspects may be coerced into confessions for fear of longer sentences

even though they are innocent

• Eyewitness Accounts by Victims or Witnesses• Eyewitness accounts vary considerably from person to person• Eyewitness accounts are unreliable and have led to the imprisonment of

many wrongfully convicted suspects» INNOCENCE PROJECT – Project with aim to free wrongfully convicted

• 87% of all wrongful convictions were a result of flawed eyewitness testimony

• Evaluation of Physical Evidence Retrieved From the Crime Scene• Only physical evidence is free of inherent error or bias• Relies on science

Functions of a Forensic Scientist• Find, examine, and evaluate evidence at a crime scene

• Observational skills are key!• Must observe whole crime scene

– Avoid tunnel vision– Collect all evidence and don’t jump to conclusions

• Use analytical skills to examine evidence and draw conclusions– ANALYTICAL SKILLS = the ability to identify a problem, isolate its

component parts, organize information for decision making, and evaluate information to draw conclusions

– Using DEDUCTIVE REASONING- using logic while studying all known facts to come to a conclusion

• Act as expert witnesses for prosecution or defense attorneys

Crime Labs

• Nearly Four hundred public crime labs in US– More than 3 times that of 1966

• Growth due to…– Supreme court cases in 1960’s placed more

emphasis on police securing scientifically evaluated evidence

– Increased Crime Rates– Increased Drug Abuse- All evidence from illicit

seizures must be sent to crime Lab for chemical analysis

Crime Lab Challenges• Not enough labs to keep up with needs• DNA Profiling (Fingerprinting)- Major Reason for increased

Demand– Technology did not exist prior to early 1990’s– Traces of Blood, Saliva, Hair, Epithelial Tissue (Skin), and Semen backlog

crime labs– Over 57,000 unanalyzed case samples– Untested convicted offender samples over 500,000– Tested samples go to CODIS (National DNA Databank)

• Combined DNA Index System

– Some states have own Database– CA over 1 million in state database

» 3rd Largest in world» Starting in 2008 all people arrested and suspected of felony charges were profiled

Types of Crime Laboratories

• Federal Crime Laboratories– FBI Crime Lab (Quanitico Virginia), largest in WORLD– DEA, and Bureau of Alcohol, Tobacco, Firearms, and Explosives

located within– Will offer assistance and expertise to state and local agencies

• State and Local Crime Laboratories– State Labs, Most States Have State Lab

• Some have statewide system with regional satellite labs

– County and Municipal Crime Labs• Some Counties have• Larger Cities, NY city is largest.• Many smaller cities do not have due to cost

Specialty Units With Full Service Crime Laboratories

• Biology Unit (Staffed w/ Biologists and Biochemists)– DNA Profiling– Blood Evidence and Other Bodily Fluids– Hair and Fiber Analysis– Plant Materials Such as wood and Plants

• Firearms Unit – Ballistics (Bullet and Firearm Analysis)– Gun Powder Residue– Crime Scene Reconstruction (Distance from which weapons are fired)

• Document Examination Unit– Handwriting and Typewriter Analysis – Ink and Paper Analysis– Erasures/Depressions

Specialty Units With Full Service Crime Laboratories (continued)

• Photography Unit– Examines and records physical evidence through photography– Sometimes advance techniques used (infrared, X-Ray, digital

imaging ect…)• Toxicology and Drug Analysis Unit

– Examines Body Fluids and Organs– Detect Presence or absence of drugs and poisons– Evidence may be sent to separate 3rd party facility– Often maintain field instruments such as Intoxilyzer

• Fingerprint/Latent Fingerprint Unit– Fingerprint Analysis

Specialty Units With Full Service Crime Laboratories (continued)

• Polygraph Unit– Lie Detector– Investigator tool yet not forensic scientist tool– Still kept in crime lab unit though

• Voiceprint Analysis Unit– Use sound spectrograph that transforms speech in to visual display

called voiceprint– Analyze recorded voice evidence (Tape recorder/phone calls ect…)

• Crime Scene Investigation Unit– Collect and preserve physical evidence that is later analyzed at crime lab– Must maintain chain of custody and check evidence in to evidence room

Other Forensic Science Services• Forensic Psychiatry

– Used in criminal and civil proceedings• Determine competence• Evaluate behavioral disorders

• Forensic Odontology– Id victims in unrecognizable state– Bite mark analysis

• Forensic Engineering– Failure analysis (buildings)– Accident reconstruction

• Examine, photograph, and review of mechanical objects

• Forensic Computer and Digital Analysis– Newest and fastest growing– Identification, collection, preservation, and examination from computers and other

digital devices