Law enforcement officials said they believed the mail bombs were the latest in a series of deadly parcels that gave been mailed or placed by the bomber since May 2, 1978. The bombs have injured 21 people and killed one, Campbell Scrutton, the owner of a Sacramento computer shop, on Dec. 11, 1985. While most of the bombs apparently have been sent to people who work extensively with computers and in high-tech fields, investigators have been at a loss to establish a more concrete pattern and motive. Three federal agencies and scores of local law enforcement officials have spent years trying to track down the bomber, who is also believed to have been behind bombings at universities in California, Illinois, Michigan, Tennessee and Utah. In 1980, he sent a bomb the Lake Forest, Ill., home of Percy Wood, president of United Airlines, who was injured in the blast.
Authorities say the bombs have become progressively more complex over the years.