BOCA RATON, Fla.?The FBI is investigating the possibility that the anthrax bacteria detected in two Florida men is a result of terrorism or criminal action, The Associated Press has learned.

The bacteria that killed a man last week has been detected in the nose of a co worker and on a computer keyboard in the newspaper office where both men worked, health officials said Monday.

?The FBI has been unable to find a source or cause of the anthrax, but this kind of situation points to terrorism or criminal intent because it?s so rare to have two people working in the same building who have inhaled anthrax bacteria,? a senior law enforcement official said, speaking on condition of anonymity.

The FBI has sealed off the office building and is combing it for clues. Any workers in the building with flu-like symptoms will be tested for anthrax, officials said.

White House spokesman Ari Fleischer would not rule out terrorism as a possible explanation.