As cunning as the Unabomber has proved to be, he may long ago have inadvertently given the FBI identifying evidence, simply by licking stamps and envelopes he then mailed, criminalists said yesterday.
Even scant cells in old, dried saliva can yield enough DNA to link a suspect to a crime or location, the forensic scientists said in commenting on reports that the FBI might have DNA samples from the Unabomber.
"I imagine one of the first things they did was collect hair and blood samples" from the Unabomber suspect, Theodore J. Kaczynski, after he was arrested Wednesday, said Thomas Wahl, a criminalist with the Las Vegas Police Crime Laboratory.
Those samples would yield cells whose nucleus contains DNA that has a unique pattern of genetic variations, Mr. Wahl said. Then, if the FBI has in its freezers a supply of DNA extracted from postage stamps or envelopes sent by the Unabomber, it should be fairly easy to compare them and -- if they prove identical -- conclude that Mr. Kaczynski sent those items, he said.
But if the Unabomber is as brilliant as he seems to be, Mr. Wahl said, "he might have moistened his envelopes and stamps with a water-soaked pad," and no DNA would be found.
He and other specialists said yesterday that DNA from saliva has served as key evidence in many criminal cases. Even before DNA testing was available, forensic experts could occasionally identify saliva from envelopes or cigarette butts or teeth marks by analyzing blood proteins in it, they said.
Pub Date: 4/05/96