BANGOR (AP) – An Augusta man was sentenced to nine months in federal prison Friday for mailing two letters containing threatening messages and a white powder to former co-workers after being fired from his job.

Darren M. Ellis, 38, mailed one of the letters in July 2002 to a vice president of Frank Pomerleau Inc. in Augusta, where Ellis had worked until he was dismissed four months earlier, the U.S. attorney’s office said.

Fearing the substance was anthrax, police had it analyzed at a state laboratory where it was determined to be consistent with flour.

Ellis also mailed a second letter to the company’s warehouse manager, according to court records.

That letter was confiscated by the Augusta Post Office after it burst open before it was delivered.

The letters were later linked to Ellis through fingerprints, prosecutors said.

Ellis pleaded guilty in August.