Transcript Slide 1
Chapter Thirteen Evidence Handling Evidence Handling Physical Evidence is any object, regardless of the size of the object that can connect a suspect to a crime or crime scene. Types of evidence • • • • • • • • Fingerprints Tool marks Clothing Blood Video Eye witness Parts,or debris left at scene D.N.A Chain of evidence • Procedures that must be followed when police deal with physical evidence in order to meet court standards for the admissibility of evidence in court. • Before moving evidence photograph and sketch it. Obtaining evidence • How, when, and were the evidence was obtained. Each area should be searched at least twice by at least two officers. • How the evidence helps to establish the guilt of the suspect. • Who has handled the evidence and for what purpose. • Where the evidence has been stored. • The evidence produced in court is the same evidence that had originally located and analyzed. • Evidence should be sealed to insure that it has not been altered or changed. • Store in a secured evidence room Locating and collecting evidence • Officers on the scene of a crime have a responsibility to protect and secure the crime scene. • There are several ways of collecting evidence. • A grid search • Zone or Quadrant • Circle or spiral • Strip or lane • Put case number date and time found, where and the finding officer’s identification. Considerations for searching a crime scene • The Fourth Amendment. • Utilize a standard pattern search. • What is missing may be evidence. • • • • • • • • • • • • Packaging evidence Paper bags and boxes Plastic bags or zip lock bags Glass vials Masking tape or Evidence tape Gloves Tweezers Dusting powder Envelopes Markers,Pencils or pens Department issue camera Call department I.D. technician State crime lab Evidence Analysis • Photography – Used to make a record of items which may change over time • Emission Spectrograph – Analyzes the composition of evidence • Microscope – Used to enlarge a viewer’s ability to see • Gas Chromatograph – Used to identify different types of gases and gaseous substances such as in arson cases. • Intoxilyzer – Used in DUI cases Evidence Analysis • Videotape – Used to record events • Identikit or Computer Programs – Used to develop a picture of a suspect from descriptions • Laser – Used to detect evidence with different light waves • DNA – Deoxyribbonucleric acid order and sequence, the organic substance found in cells, except twins, individually unique. Evidence Analysis • Blood – Determine if animal or human, blood type, DNA. • Explosives and arson debris – Method of detonation, composition, components manufacturer. • Fabric / Fiber – Color, pattern, thickness, weave, type of material, and manufacturer. • Gunshot residue (GSR) – Test can determine if subject has recently fired a gun. Evidence Analysis • Serial Numbers • Bullets, Cartridge Casing – It can be determined if a bullet was fired from a specific gun if the weapon has rifling such as a .357 magnum or .40 caliber but not from a shotgun. • Glass – It can be determined if a particular fragment came from a broken object, type of glass, direction of force • Hair – Determine human or animal, race, if dyed, forcibly removed, eating and drinking habits, drug use, possible DNA Evidence Analysis • Tool Marks – Comparison of tools and marks • Ink – Brand, type, date manufactured, document age • Paint Chips – Layers and types, comparison to other samples, color, year of vehicle • Paper – Year of manufacture, erasures, alterations, secret writing Evidence Analysis • Teeth marks – Can be matched to a suspects bite and used in court. • Footprints – Matched to foot or shoes. Polygraph test • Not mandatory in Utah • Are not usually admissible in court • They are not 100% accurate – Only 90 to 95% accurate Finger prints Humans have ridges on fingers, palms, toes, and feet to help grasp or grip items. • • • • Three types Loop Arch Whirl Latent fingerprint • Is a fingerprint that is left at the crime scene and is not visible. History of fingerprints • First used in 1902 in the U.S in order to stop cheating on the civil service exam. • The F.B.I serves as the fingerprint storage facility in the U.S. • Automated fingerprint identification system (AFIS) • Utah is part of the western identification network also. (WIN) consist of nine western states Fingerprint Identification • 60% of the population have loop patterns • 35% of the population have whorl patterns • 5% of the population have arch patterns Analysis of evidence • • • • • • • • • Fibers Hair Blood Guns Bullets Calibers Serial numbers Explosives Ink • • • • • • • • • Glass Body fluids D.N.A G.S.R Tool marks Paint Teeth marks Foot prints Paper Autopsy • Is a medical procedure performed by a doctor where a body is examined to determine the contributing manner, mode and cause of death. • This is performed by the state medical examiner. Who gets the autopsy • Dead people who die in the following manner: – – – – – – Death by violence,gunshots, suicide, accident. Sudden death while in apparent good health. Unattended deaths, Suspicious deaths. Poisoning, overdoses of drugs . Diseases, injury’s, toxic effects over exertion during employment. Death at a state medical facility, prison, or a jail and a mentally ill person in custody. – S.I.D.S. – Death associated with diagnostic and therapeutic procedures.