FBI to open Leahy anthrax letter Friday

WASHINGTON (CNN) -- FBI officials told CNN they will open an anthrax-contaminated letter addressed to Sen. Patrick Leahy, D-Vermont, on Friday.

The letter, discovered and quarantined November 16, will be opened by experts at Fort Detrick, a germ warfare research lab in Frederick, Maryland, about 40 miles from Washington, FBI officials said. They did not provide a timetable, but denied reports the letter would be opened by "robot."

A group of scientists from the FBI, the U.S. military and at least three nongovernmental scientists will examine, open and study the contents, officials have said.

Sources earlier had told CNN that authorities had established a precise protocol on handling the letter and its contents as a way to minimize damage to any clues that could help determine the identity of the sender.

An FBI-led team of investigators wearing hazardous material suits found the letter from among thousands set aside after a similar envelope to Senate Majority Leader Tom Daschle, D-South Dakota, was discovered in October. That envelope contained an anthrax-laced letter.

Experts hope this sample will be the most pristine of any anthrax recovered so far because fewer people have handled the envelope and its contents.

The FBI has already determined that the anthrax that leaked from the Leahy envelope has the same high level of purity as the anthrax found in the Daschle letter.