- Information
- AI Chat
Chapter 3 Forensic Science
Forensic Science (CHEM1118)
Fairleigh Dickinson University
Recommended for you
Preview text
Physical Evidence
● Common Types of Physical Evidence ○ Blood, semen, and saliva ■ All suspected blood, semen, or saliva - liquid or dried, animal or human - present in a form to suggest a relation to the offense or persons involved in a crime. ○ Documents ■ Any handwriting and typewriting submitted so that authenticity or source can be determined. ○ Drugs ■ Any substance seized in violation of laws regulating the sale, manufacture, distribution, and use of drugs. ○ Explosives ■ Any device containing an explosive charge, as well as all objects removed from the scene of an explosion that are suspected to contain the residues of an explosive. ○ Fibers ■ Any natural or synthetic fiber whose transfer may be useful to establishing a relationship between objects and/or persons. ○ Fingerprints ■ All prints of this nature, latent and visible. ○ Firearms and ammunition ■ Any firearm, as well as discharged or intact ammunition, suspected of being involved in a criminal offense. ○ Glass ■ Any glass particle or fragment that may have been transferred to a person or object involved in a crime. ○ Hair ■ Any animal or human hair present that could link a person with a crime ○ Impressions ■ This category includes tire markings, shoe prints, depressions in soft soils, and all other forms of tracks. ○ Organs and Physiological Fluids ■ Body organs and fluids are submitted for toxicology to detect possible existence of drugs and poisons. ○ Paint ■ Any paint, liquid or dried, that may have been transferred from the surface of one object to another during the commission of a crime. ○ Petroleum Products ■ Any petroleum product removed from a suspect or recovered from a crime scene. ○ Plastic Bags
■ A polyethylene disposable bag such as a garbage bag may be evidential in a homicide or drug case. ○ Plastic, Rubber, and other Polymers ■ Remnants of these man-made materials recovered at crime scenes may be linked to objects recovered in the possession of a suspect perpetrator. ○ Powder Residues ■ Any item suspected of containing firearm discharge residues. ○ Serial Numbers ■ This category includes 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. ○ Tool Marks ■ This category includes any object suspected of containing the impression of another object that served as a tool in a crime. ○ 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. ○ Wood and 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. ● The Significance of Physical Evidence ○ The examination of physical evidence by a forensic scientist is usually undertaken for identification or comparison. ● Identification ○ Identification has as its purpose the determination of the physical or chemical identity of a substance with as near absolute certainty as existing analytical techniques will permit. ○ Identification Definition ■ The process of determining the substance’s physical or chemical identity. Drug analysis, species determination, and explosive residue analysis are typical examples of this undertaking in a forensic setting. ● Comparison ○ A comparison analysis subjects a suspect specimen and a standard/reference specimen to the same tests and examinations for the ultimate purpose of determining whether or not they have a common origin. ■ The process of ascertaining whether two or more objects have a common origin. ● Individual Characteristics ○ Evidence that can be associated with a common source with an extremely high degree of probability is said to possess individual characteristics.
Chapter 3 Forensic Science
Course: Forensic Science (CHEM1118)
University: Fairleigh Dickinson University
