BOCA RATON, Fla. - Two post offices reopened Friday, a day after anthrax was found in areas where a tainted letter may have passed through before arriving at a tabloid publisher where an employee died of the disease

Tiny amounts of anthrax spores were removed from the Boca Raton distribution center that handled American Media mail and the Lake Worth post office that once processed mail for The National Enquirer and Weekly World News, health officials said.

Postal officials said a tainted letter could have passed through both buildings before arriving at American Media headquarters in Boca Raton. Anthrax spores were found earlier at a second post office in Boca Raton.

Postal Service spokesman Joseph Breckenridge said it was possible that one letter could infect all the locations. For example, a letter sent to an old address for the tabloids could have been rerouted through the facilities.

In Washington, Homeland Security Director Tom Ridge said anthrax strains discovered in Florida, New York and Washington are virtually identical. The source has not been determined, but the anthrax has raised fears of biological warfare following the Sept. 11 attacks by terrorists aboard hijacked jetliners.

The scare in Florida began earlier this month when Bob Stevens, a photo editor at The Sun tabloid, died of inhaled anthrax. A mailroom co-worker, Ernesto Blanco, is infected with the same form of the disease.

Blanco, 73, is recovering at a Miami hospital. Hundreds of American Media employees are waiting for test results to see if they were exposed to anthrax. Many are being treated with antibiotics as a precaution.

In West Palm Beach, investigators said tests were negative for anthrax on a letter without a return address that was mailed to the FBI and postmarked Trenton, N.J. _ the city where anthrax-tainted letters were sent to NBC in New York and the Senate majority leader in Washington.

Meanwhile, police in nearby Delray Beach said one of the suspected hijackers, Mohamed Atta, was given only a warning during a July traffic stop even though there was a warrant out for his arrest.

Officer Scott Gregory stopped Atta for speeding on July 5. He would not have known Atta was wanted in neighboring Broward County for failing to appear in court in June for driving without a license, police Capt. Ralph Phillips said Friday.

Gregory checked Atta on national, state and Palm Beach County computer systems, but information about minor warrants is not put into state and national systems to prevent computer crashes, Phillips said.

Many warrants, like the one issued for Atta, are available by computer only to officers in the county where they were issued, Phillips said.

"If all of them were put in, it would lock down the system," he said. "So you only put in the more heinous misdemeanor or felony warrants."

Authorities believe Atta flew one of the jetliners into the World Trade Center. He listed Coral Springs in Broward County as his residence and traveled frequently around the state, taking flying lessons and visiting others believed to be involved in the hijacking plot.

Phillips said Gregory does not remember his encounter with Atta. The warning does not say how fast Atta was going, only that he had a license and was exceeding the 25-mph speed limit.

Even had Atta been arrested and received the maximum punishment of 60 days in jail, he would have been released well before Sept. 11.