A detective working a missing persons case undoubtedly knows how to make the most of databases such as the Combined DNA Index System (CODIS) and the Integrated Automated Fingerprint Identification System (IAFIS), but does he or she know how to investigate a paint chip, a tire track, an ink sampling, or a piece of glass?
Many government and private forensic databases can help both law enforcement investigators and the scientists who support their work in the lab.
Because the database contains information on bullets and casings—and not on specific guns—a test-fire bullet from a gun must be compared to a bullet found at a crime scene, for example, to determine whether a bullet came from a specific gun.
Any image of a casing or bullets must be sufficiently clean—that is, be clear, show characteristics, and have little glare—for a comparison to be valid. Technicians use forensic imaging technology to enter bullet and casing evidence into IBIS.
New images are correlated against data, and technicians are alerted to possible matches.
At that point, a firearms examiner uses a comparison microscope to perform a manual examination. Maintained by the Royal Canadian Mounted Police (RCMP), PDQ contains the chemical compositions of paint from most domestic and foreign car manufacturers and the majority of vehicles marketed in North America after 1973.
by Robin Bowen and Jessica Schneider About the Authors Ms.
Bowen is the forensic program coordinator for the Forensic Science Initiative at West Virginia University. Schneider is a graduate student in public administration at West Virginia University.
If studying to become a forensic science technician, each class has its own set of textbooks and other reading assignments.
But how does the average student keep up with the latest cases and tech advancements without paying costly subscription fees?
These known samples are compared against a paint sample from a crime scene or a suspect’s vehicle to search the make, model, and year of manufacture of a vehicle involved in a hit-and-run or other criminal activity. This Federal Bureau of Investigation (FBI) database contains more than 40,000 samples of automotive paint from manufacturers. Paint chips from cars can be compared to samples in the database.
Undercoats help to narrow down possible manufacturers. Although it cannot determine the source of an unknown piece of glass, the database can assess the relative frequency that two glass samples from different sources would have the same elemental profile. Two plasma mass spectrometers are used to perform an elemental analysis of glass. The number of shoe prints at a crime scene can be so large that the process of impression recovery becomes very time-consuming.
One limitation is that different manufacturers often use the same sole unit.