A federal grand jury indicted Thursday a 66-year-old retired teacher from Sacramento who sent 120 letters with fake anthrax nationwide last month to alert the public on the threat of bioterrorism.

Marc M. Keyser faces 10 counts of hoax mailings and three counts of mailing threatening communications. Both crimes are punishable by up to 70 years imprisonment.

Keyser, who is out on a $25,000 bail, has said he was not sorry for sending the letters with compact discs and packets of sugar labeled as anthrax to media and government offices as well as restaurants because he was just trying to prompt the government to be vigilant in preventing a repeat of the anthrax mail attack in 2001 that killed five people and sickened 17 others.

"I'm not sorry," Keyser told KCRA 3 Thursday during an interview at the Sacramento County Jail. "I don't consider myself a criminal. I'm just trying to convince people that they need to know the danger we are facing. I feel people are underestimating the dangers we are facing from terrorism."

Keyser was arrested two weeks ago as the hoax letters contained his return address. He was also charged with hoax mailing last year.