August 6, 2008 Justice Dept.: Ivins 'only person responsible' for anthrax attacks Play video

(NECN: Washington) - The FBI and the Department of Justice held a news conference this afternoon on the anthrax investigation.

U.S. Attorney Jeffrey Taylor is confident that Bruce Ivins was the only person responsible for the 2001 attacks and that they could have proved his guilt beyond a reasonable doubt. The U.S. attorney says Ivins had a history of mental health problems.

Army scientist Bruce Ivins had sole custody of highly purified anthrax spores with "certain genetic mutations identical" to the poison that killed five people and rattled the nation in 2001, according to documents unsealed Wednesday in the government's investigation.

A memorial service was held today for Ivins.

Investigators also reported tracing back to Ivins' lab the type of envelopes used to send the deadly spores through the mails.

The scientist, depicted in the newly released papers as deeply troubled, committed suicide last week as investigators were preparing to charge him with murder in the attacks.

The documents were released as the FBI held a private briefing for families of the victims of the episode, and officials said the agency was preparing to close the case.

More than 200 pages of documents were made public by the FBI, virtually all of them describing the government's attempts to link Ivins to crimes that his lawyer has said he did not commit.

*Material from the Associated Press used in this report*