Anthrax letter could yield clues

The letter never reached its destination

By the BBC's Helen Sewell

Bio-terrorism experts in the United States are about to begin the delicate process of opening an envelope, which is known to contain potentially fatal anthrax spores.

It is the first time experts have had the chance to open a contaminated letter and they are expected to open it on Friday.

Mr Leahy said the letter could have killed 100,000 people

They hope that as well as retrieving all the dangerous spores from the envelope, they will manage to recover fingerprints and human DNA as well, which could help reveal who sent the letter.

The letter was sent to US Senator Patrick Leahy, the chairman of the Senate Judiciary Committee, on 9 October.

But because of stringent safety precautions, it never reached him.

Leaked spores

Instead it was placed in one of hundreds of sealed bags of congressional mail, where it stayed until mid-November, when it was detected by FBI officials.

By that time, scientists say, it had leaked enough spores to contaminate dozens of other bags.

Senator Leahy said it contained enough anthrax to kill 100,000 people.

Robot assistant

The envelope is now sealed within several plastic bags and kept under lock and key in a low humidity fridge while army scientists and the FBI work out how to open it safely, yet delicately enough to retain clues such as fingerprints or DNA evidence.

These, they hope, could lead them to the sender.

For the past two weeks they have been conducting practice runs on uncontaminated envelopes, with the help of a small robot, to ensure their techniques will actually work.