Samples taken from the State Department's main mail-sorting facility in Sterling, Va., tested positive for anthrax spores, a State Department official said Tuesday.

Eight of 55 samples taken from machinery and sorting areas were positive. The contaminated samples came from three automated mail sorters, one of which had six positive samples while the other two had one each.

State Department spokesman Richard Boucher said the finding supports the theory that a "contaminated letter in our system" resembles one sent to Senate Majority Leader Tom Daschle, D-S.D.

Authorities can't rule out there could be more than one contaminated letter since more than one sorting machine had positive samples, Boucher said.

It's impossible to tell at the moment where a contaminated piece of mail may be located right now. The entire State Department mail system was shut down Oct. 24 and mail rooms were sealed. All mail pouches and overseas mailrooms were also sealed, but it's possible the original letter may have gotten to its destination before the areas were sealed.

Efforts are now underway to find the original contaminated letter or letters. The State Department is searching through all its held-up mail both in the United States and overseas.

Boucher also confirmed that results of a suspected contaminant at the U.S. embassy in Lima, Peru proved to be anthrax. The mailbag in which the anthrax was found was sent out on Oct. 22, after being in the mail facility for about a week. Lima receives diplomatic mail pouches from the State Department once a week.

Further environmental testing showed that only one mailroom, rather than two, in the main State Department building tested positive in addition to the diplomatic security mailbag in an annex across the street.

A mail worker from the State Department's remote mail processing center where the anthrax was found was released from the hospital on Friday.