Key points of U.S. evidence in anthrax probe

(Reuters) - Army scientist Dr. Bruce Ivins was the only person responsible for the U.S. anthrax attacks that killed five people after September 11, 2001, federal authorities said on Wednesday.

Lawyers for Ivins called the federal case "innuendo" without real evidence, but the U.S. government plans to close the investigation following Ivins's suicide death last week. Following are key points of evidence outlined by the government in documents released by a federal court:

* Ivins created and maintained in a flask the parent material of anthrax spores used in the attacks, and controlled all access to it. Investigators used genetic "fingerprint" analysis to pinpoint the flask and they ruled out as suspects all other people with access. A prosecutor called the flask "effectively the murder weapon."

* Ivins worked unusual night-time and weekend hours in the anthrax lab in the days leading up to each mailing of anthrax-tainted letters in September and October 2001. Investigators deemed unsatisfactory his explanations, such he wanted to "escape" his home life.

* Ivins showed a "consciousness of guilt" by submitting a questionable anthrax sample from the flask of parent spores to the FBI "presumably to mislead investigators" and telling a group therapy session that he expected to be indicted but would kill people who had wronged him.

* He sent an e-mail shortly before the anthrax attacks warning that Osama "bin Laden terrorists for sure have anthrax and sarin gas" and had "just decreed death to all Jews and all Americans." The wording was similar to the warning in the anthrax letters.

* He had a fascination with Kappa Kappa Gamma sorority and viewed himself as an expert on it. The sorority has an office 60 feet (20 metres) away from the Princeton, New Jersey mailbox used in the mailings.

* The envelopes used in the mailings were very likely sold at a post office in the Frederick, Maryland, area in 2001. Ivins maintained a post office box at a Frederick post office where some of the envelopes were sold.

(Reporting by Randall Mikkelsen and Jackie Frank)