Scientist had 'sole custody' of anthrax

A US army scientist had sole custody of highly purified anthrax spores with "certain genetic mutations" identical to the poison that killed five people in 2001, it emerged yesterday.

Documents unsealed as part of the government's investigation also reported tracing the type of envelopes used to send deadly spores through the post to the lab where Bruce Ivins worked.

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

The documents were released as the FBI held a private briefing for families of the victims, and officials said the agency was preparing to close the case. More than 200 pages of documents were made public, virtually all of them describing the attempts to link Ivins to crimes that his lawyer has said he did not commit.

Ivins had submitted false anthrax samples to the FBI. He was also said to have been immunised against anthrax in early September 2001, weeks before the first anthrax-laced envelope was received in the post.