In less than a minute, checks using offerings from Digital Directory Assistance and Pro CD produced the address of a "T. Mosser" even though both products listed it as being in nearby Caldwell, rather than North Caldwell.
Neither listed Mr. Mosser's occupation. However, both made it clear that no other Tom Mosser or T. Mosser with a listed phone number lived anywhere else in the New York metropolitan area.
Mr. Mosser, who had just been named general manager of Y&R, was killed Dec. 10 when a package bomb exploded in his home. Investigators said the package, shaped like a videocassette, was mailed Dec. 3 from San Francisco.
Police and the FBI blame the death on a bomber who has killed two people, including Mr. Mosser, and injured 23 others.
They are continuing to investigate the bombing, and a $1 million reward has been offered.
A phone number, 1-800-701-BOMB, has been set up to take tips.
How the bomber obtained Mr. Mosser's address is "one avenue of the investigation," said Rick Smith, an FBI special agent in San Francisco.
He said investigators are also trying to understand why Mr. Mosser was targeted since most of the previous victims were at universities.
"On the surface it appears to be an anomaly," said Mr. Smith. "He was not an academic."
The reward has produced more than 8,000 calls and tips, authorities said.
A 25-to-30-member task force of FBI agents, police, U.S. postal inspectors and agents of the Bureau of Alcohol, Tobacco & Firearms continues investigating the cases on a full-time basis, Mr. Smith said.