Physical evidence – consists of tangible articles found at a crime scene that can be introduced in a trial to link a suspect or victim to the scene

A law which sets the maximum period in which one can wait before filing a lawsuit Personal/civil lawsuit Crime The period of time depends on: State Type of crime

Civil cases – involve private disputes between persons or organizations Example: personal injury Criminal cases – involve an action that is considered to be harmful to society as a whole Example: murder

Civil Cases Assault/battery – 2 years False imprisonment – 2 years Personal injury – 2 years

Criminal Cases Assault – 1-5 years Rape – no limit Murder/manslaughter – no limit Kidnapping – 5 years

Time does not start to run until the State is in possession of both the physical evidence and the DNA or fingerprint evidence necessary to establish the identification of the actor by means of comparison to the physical evidence.

Investigator must be able to: Make logical decisions Process the uncommon and unexpected Qualified evidence collectors must be able to make innovative and on-the-spot decisions at the crime scene

Blood, semen, and saliva In dried or liquid form Blood or semen can be found on fabrics or other objects Saliva can be found on cigarette butts or letters Serological and biochemical analysis to determine identity and origin

Blood, semen and saliva continued Tested for DNA Saliva – DNA from cheek cells Evidence goes to Biology unit

Documents Handwriting and typewriting submitted so authenticity or source can be determined Questioned Documents

Documents Analysis is of: Paper Ink - forgeries Indented writings Burned/charred documents Evidence goes to Questioned Document Unit

Drugs Any substance seized in violation of laws regulating the sale, manufacture, distribution and use of drugs Presumptive test – analysis of sample which establishes either 1. sample is definitely not a certain substance or 2. the sample probably is the substance Presumptive test

Drugs Confirmatory test – test required to confirm analysis, done in the lab Evidence goes to either Toxicology or Physical Science Unit

Explosives Any device containing an explosive charge Includes objects removed from the scene of an explosion that may contain explosive residues

Explosives Presumptive tests can also be used on explosives

Fibers Natural or synthetic fiber whose transfer may be useful in establishing a relationship between objects or people Types of fibers: Nylon, silk, cotton, kevlar

Fibers Often from clothing or some type of fabric Cannot be individualized most of the time Can you think of a time when it can? Evidence sent to Physical Evidence Unit

Fingerprints Individual to each person (no two people have the same fingerprints) Includes latent and visible fingerprints Latent prints – fingerprints that cannot be seen to the naked eye – dusting or superglue fuming used superglue fuming

Fingerprints Fingerprints can be found on almost any type of surface – less likely found on porous surface such as skin or clothing but not impossible! Evidence sent to Fingerprint Unit

Firearms and Ammunition Any firearm, as well as discharged or intact ammunition, suspected of being involved in a criminal offense Bullet casings as well as recovered bullets that were shot

Firearms and ammunition Striations on bullets are often compared to determine weapon used Evidence sent to Ballistics Unit

Glass Any glass particle or fragment that may have been transferred to a person or object involved in a crime Includes window panes containing holes made by a bullet or other projectile

Glass Characteristics analyzed include: color, thickness, optical properties, density, direction of force Evidence sent to Physical Evidence Unit

Hair Any animal or human hair present that could link a person with a crime Hair is class or individual based on what? Analyzed using comparison microscopes

Hair Hair can be found at any type of crime scene, not necessarily just murder and assault Evidence sent to either Biological Unit (if ripped out of scalp) or Physical Evidence Unit

Impressions Can be made by multiple sources Tire markings, shoe prints, depressions in soft soils This includes also glove and fabric impressions and bite marks

Impressions Casts are often made of the impressions so that they can be compared to possible sources Also to prevent the loss of the impression Evidence sent to Physical Science Unit

Organs and physiological fluid (organs not normally found at crime scene) Body organs and fluids are submitted to toxicology to detect possible existence of drugs and poisons Blood is included as a fluid

Organs and physiological fluid Collected by a pathologist who performed the autopsy Organs and fluid sent to Toxicology unit for further analysis

Paint Can be liquid or dried Any paint that may have been transferred from the surface of one object to another during a crime Most common example: automotive paint In car accident or hit and run

Paint Paint analysis is done using GC-MS in a lab – the chemical components of the paint are used to determine its origin Automotive paint – layers of colors help determine origin Evidence sent to Physical Science Unit

Petroleum products Petroleum = fuels such as gasoline, kerosine, and diesel oil Any petroleum product removed from a suspect or recovered from a crime scene Most common: gasoline residues removed from the scene of an arson

Petroleum products The type of petroleum product can be determined using GC-MS Evidence most likely sent to Physical Evidence Unit

Plastic Bags A disposable polyethylene bag such as a garbage bag may be evidential in a homicide or drug use Examinations are conducted to associate a bag with a similar bag in the possession of a suspect

Plastic Bags Trace evidence such as hair or fibers can also be found on plastic bags in homicide cases Evidence sent to Physical Science Unit

Plastic, rubber and other polymers Remnants of these manufactured materials recovered at crime scenes may be linked to objected recovered in the possession of a suspect perpetrator Evidence sent to the Physical Science Unit

Powder Residues Any item suspected of containing firearm discharge residues Powder residues can also include drugs in powder form By looking at the powder it is impossible to determine the identity and its origin

Powder Residues Depending on the suspected identity the evidence can go to either Ballistics Unit, Toxicology Unit or Physical Evidence Unit

Serial Numbers Serial number – unique code assigned for identification of a single unit Often found on any electronic as well as vehicles

Serial Numbers Crimes involving stolen property often have the serial numbers erased (scratched off) All stolen property submitted to the laboratory for the restoration of erased identification numbers

Soil and Minerals All items containing soil or minerals that could link a person or object to a particular location Soil/minerals can be found under shoes of suspects or on victims

Soils and minerals Depending on the composition of the soils, the location of origin can be determined Evidence sent to Physical Science Unit

Tool Marks Any object suspected of containing the impression of another object that served as a tool in a crime A screwdriver or crowbar would produce tool marks by being impressed into or scraped along a surface of a wall

Tool Marks Tool marks also falls under firearms and ammunition because a gun is considered a tool and leaves its marks on bullets (where hammer hits bullet) Evidence sent to Physical Science Unit

Vehicle Lights Examination of vehicle headlights and taillights is normally conducted to determine whether a light was on or off at the time of impact Physical Evidence Unit

Wood or other vegetative matter Any fragments of wood, sawdust, shavings or vegetative matter discovered on clothing, shoes or tools that could link a person or object to a crime location Each wood and vegetative matter has its own microscopic characteristics

Wood and vegetative matter Evidence sent to Physical Evidence Unit Tree only grows in Hawaiian cloud forest Tree only grows in Mediterranean

3 types of evidence Physical (already known) Personal – description or account of what was seen or heard (eyewitnesses) Circumstantial – evidence that requires an inference Indirect evidence that implies something has occurred Does not prove anything happened

Woman is accused of embezzling money from her company Makes big ticket purchases in cash around the time the money was taken Wife is suing her husband for divorce claiming he had an affair Another woman’s fingerprints were found in the bedroom – doesn’t prove affair but implied because why else would they be there?

Identification – determining object/substance identity Testing procedures needed Problems – each type of evidence require different tests Multiple tests used to support accuracy

You need collected specimen (evidence) and a control Both evaluated under the same set of tests and examinations Use specific properties Determine if they have common origin

Individual vs. Class Do you remember the difference?

Inceptive vs. corroborative Inceptive At the start of an investigation Evidence to base a search for a suspect Corroborative At the end of an investigation Evidence used to prove or disprove

Aka CSI syndrome or CSI infection Any of several ways in which the exaggerated portrayal of forensic science on crime television shows such as CSI: Crime scene investigation influences public perception