U.S. flag

An official website of the United States government, Department of Justice.

NCJRS Virtual Library

The Virtual Library houses over 235,000 criminal justice resources, including all known OJP works.
Click here to search the NCJRS Virtual Library

Forensic Sciences, Parts 1, 2 and 3 - Physics and Chemistry, Questioned Documents and Polygraphs

NCJ Number
84449
Author(s)
Anonymous
Date Published
Unknown
Length
0 pages
Annotation
FBI laboratory experts discuss forensic evidence analysis techniques and preparation for trial, document analysis, and polygraph techniques and interrogations.
Abstract
Speakers recommend that prosecuting attorneys use the Handbook of Forensic Science in preparing for trials. Many advances have been made in blood group identification, evidence often crucial to an attorney's case. The main blood groupings are A, B, O, and AB: M, n, and Mn; and the RH factor. The FBI laboratory has specific techniques for analyzing seminal fluid, hair and fibers, fabric, building and construction materials, glass, poison, drugs, and other substances. It also aids arson investigations and conducts neutron activation analysis and toolmark identification. Document analysis covers typewritten papers, check writing, determination of document authenticity and age, commercial printing, and handwriting. The FBI Laboratory routinely handles about 150 handwriting cases daily and can handle up to 300 if necessary. The polygraph measures a person's heart rate, blood pressure, perspiration, and other involuntary physiological responses. Psychotics and persons using drugs or alcohol are not suitable for a polygraph test. Speakers cite factors affecting the test's accuracy. Audience questions are answered throughout the presentation.