Intro to Forensic Science and Crime Laboratories

Scientific Method Science derives it’s integrity from adherence to guidelines and the scientific method Careful and systematic (orderly) collection, organization, and analysis of information/evidence The underlying principles provide a safety net to ensure that the outcome of an investigation is not tainted by human emotion or compromised by distorting, belittling, or ignoring contrary evidence

How To Be a Good Observer Pay attention to all the details of your surroundings Place personal opinions and beliefs aside Rely on direct experience and knowledge Don’t jump to conclusions Write down and photograph as much information as possible Memories are faulty

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

Types of Crime Laboratories

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 3 rd 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