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Ballistics Technology Used in Hunt for DC Area Sniper

Investigators are sifting through physical evidence left behind after a series of sniper shootings in the Washington D.C. area. The main pieces of evidence are the bullets recovered from the victims. Investigators have been able to use ballistics technology to determine the same gun was used in all the shootings.

The term "ballistics" refers to the study of a projectile in motion. Ballistics also refers to the forensic study of bullets, cartridges and firearms in criminal investigations. When a bullet travels through a gun barrel, the bullet's metal gets worn in a unique pattern by the harder metal of the barrel. Unless there has been some intentional alteration, any bullet fired by a specific gun will show the same marks.

The gun markings on a bullet or the striations, are examined and compared under a special microscope and then put into a computer.

The director of forensic services for Forensic Technology Incorporated, Richard Vaughan, says computerizing ballistics data means investigators in different parts of the country can share information with each other quickly, through what is known as the IBIS system. "What it allows is for the technology, the IBIS system, to be able to send images back and forth to other crime laboratories in an attempt to determine whether or not two different laboratories might have fired evidence from the same gun," says Mr. Vaughn.

Forensic Technology Incorporated runs IBIS, which stands for the Integrated Ballistic Information System. Not only has IBIS been used to help in the latest sniper case, it forms the basis for a national network run by the U.S. government's Bureau of Alcohol, Tobacco and Firearms.

Georgetown University professor John Copacino, director of the law school's criminal justice clinic, says evidence gathered from the bullets has proven to be important in the Washington area sniper investigation. "What the ballistics testing in this case does, is it ties all of the shootings together, so that they're able to say these were done with the same gun," he says.

Professor Copacino says investigators ideally need to find the firearm that the sniper used and test fire a bullet so it can be examined and compared to the suspect bullets. But he says if authorities are able to link a suspect to at least one of the shootings, the ballistic evidence would actually link him or her to all of the shootings. "If they can find someone and connect him by other means, other than the gun, to one of the shootings, that means he's connected to more of the shootings," says Mr. Copacino.

Since the series of shootings began October 2, the Washington area gunman has so far killed nine people and wounded three, including the latest victim, who was shot Saturday and is in critical condition in a Virginia hospital.