KING

Qwest Field

WASHINGTON, D.C. - The FBI was interviewing a Milwaukee resident Thursday believed to be responsible for posting what officials think are phony threats on a Web site about radiological dirty bomb attacks on NFL football stadiums, including a game at Seattle's Qwest Field, this weekend.

The person, described only as a young adult, did not appear to have any ties to terrorist groups, according to a law enforcement official who spoke on condition of anonymity because the investigation was ongoing.

The threats, which were posted on the Internet site a week ago, were not seen as credible and were not backed up by intelligence indicating such an attack might be imminent, according to the FBI and the Homeland Security Department.

Homeland Security on Wednesday alerted the NFL and authorities in New York, Miami, Atlanta, Seattle, Houston, Oakland and Cleveland, saying they were acting "out of an abundance of caution."

Homeland Security spokesman Russ Knocke on Wednesday said the threat was viewed "with strong skepticism." Still, the agency contacted the National Football League, local authorities and stadium owners. Also notified was the National Collegiate Athletic Association.

The online posting, dated Oct. 12, was part of an ongoing conversation titled "New Attack on America Be Afraid." It appeared on a Web site, "The Friend Society," that links to various online forums and off-color cartoons. The site's Internet provider declined to comment.

The message said trucks would deliver radiological bombs to stadiums in New York, Miami, Atlanta, Seattle, Houston, Oakland and Cleveland - and that al-Qaida leader Osama bin Laden would claim responsibility.

A dirty bomb would use conventional explosives to scatter radioactive material. Such a blast probably would not cause many deaths, experts say, but the fear of contamination could spark panic. Land and buildings hit with radioactive particles might be unusable for years.

Authorities traced the site's Internet provider to Voxel Dot Net Inc., which has support and engineering staff based in Troy, N.Y. A man who answered the phone at Voxel Wednesday declined to give his name, said he was unaware of the posted threat and refused further comment.

The author of the threats, posted at 9:31 p.m. EDT on Oct. 12, identified himself online as "javness."