TRENTON, N.J. (AP) _ Detectives looking for the source of anthrax-contaminated letters sent to NBC and the Senate majority leader are using the pre-stamped envelopes and bar codes to narrow their search.
The familiar black-and-white striped computer lines that route the mail have helped postal investigators close in on where the letters were mailed, authorities said Wednesday.
The two tainted letters were sent through a postal station outside Trenton that handles mail from 46 central New Jersey post offices.
The bar codes give a date and approximate time the letters were processed. Postal Inspector Tony Esposito said other information from the bar codes eliminated many of the post offices from the search.
Nearly all the 46 post offices have surveillance cameras and investigators are reviewing the tapes.
``We got good videotape and we're going through that,'' Esposito said. ``It's a very laborious job.''
The envelopes themselves also offer details that might lead investigators to those who mailed the bacteria. Both were bought from the postal service with printed stamps.
Postal employees said pre-stamped envelopes are not common and are usually sold a few at a time. The envelopes may be purchased at either a vending machine or a post office, postal officials said.
The prepaid envelopes have been in circulation only since July and must be moistened before they are sealed. Federal officials are testing the envelopes for DNA samples.
The first letter was sent last month to NBC anchor Tom Brokaw in New York; one of his assistants later tested positive for the skin form of the disease. The second was sent to Senate Majority Leader Tom Daschle's office in a Washington office building.
Anthrax mailed from New Jersey has brought even more attention to the state since terrorists crashed hijacked airliners into the World Trade Center, the Pentagon and a Pennsylvania field Sept. 11.
At least six of the hijackers are believed to have lived in a Paterson apartment, including Hani Hanjour, who is believed to have piloted the American Airlines jet into the Pentagon. He bought his ticket at a Totowa travel agency.
Hijacker Mohamed Atta bought a plane ticket to Spain from a Paterson travel agency in July. And Hanjour and Nawaq Alhamzi, another Flight 77 hijacker, rented at least three cars from a Wayne dealership in the weeks before the attacks.
New Jersey also figured in the investigation into the 1993 bombing of the trade center. In 1994, sheik Omar Abdel-Rahman, who preached in Jersey City, was convicted of plotting the bombing.