WASHINGTON (AP) — Advanced DNA testing led federal investigators to suspect a government scientist in the 2001 anthrax killings. The scientist’s odd behavior, suspicious e-mails and unusual work hours convinced them they had the right man.

The government declared the 2001 attacks solved Wednesday, pointing the blame at former Army scientist Bruce Ivins, who committed suicide last week as prosecutors prepared to bring charges.

Authorities cited advanced DNA testing that showed Ivins, 62, had in his laboratory anthrax spores identical to those that killed five and shocked a nation still reeling from the 2001 terrorist attacks.

Prosecutors described Ivins’ unexplained late nights in the laboratory just before the attacks. They released an e-mail excerpt that used language similar to that of one of the anthrax letters. They said he was angry about criticism of his anthrax vaccine and might have released the toxin to drum up support for his drug.