BOCA RATON, Fla.(AP) Investigators have found no further sign of anthrax in the office of a man killed by the disease since traces were found on his computer keyboard and in the nose of a co-worker, health officials said yesterday.

There have been no additional cases of contamination, Florida health department spokesman Tim O"Connor said.

Hundreds of people are waiting for test results to learn whether they were exposed to anthrax at the Boca Raton headquarters of supermarket tabloid publisher American Media.

Some worked closely with Robert Stevens, a 63-year-old Sun editor who died of anthrax Friday. Investigators say anthrax bacteria were later found on his computer keyboard and in the nasal passages of mailroom employee Ernesto Blanco, 73. Blanco was in good condition at an area hospital, O"Connor said.

The source of the anthrax, which can be used as a biological weapon, is the subject of a federal investigation involving the FBI and the Centers for Disease Control and Prevention, which has virtually ruled out environmental causes as the source.

The FBI believes the strain that infected Stevens was manmade since it does not match any known naturally occurring version, law enforcement officials in Washington said on condition of anonymity.

Investigators have not found evidence of terrorism, though the manufactured nature of the bacteria suggests criminal activity may be involved, the officials said.