WASHINGTON (AP) _ U.S. authorities are investigating the deadly takeover of a Moscow theater last year by Chechen rebels, trying to determine whether criminal charges can be brought for the death of an American.

A federal grand jury and the FBI are looking into the October 2002 attack, a U.S. government official who spoke on condition of anonymity said Wednesday. Authorities are looking into the possibility of bringing criminal charges against the organizers of the takeover.

The siege ended when the Russian government sprayed a powerful gas into the theater. More than 120 of the 800 hostages were killed, including Sandy A. Booker, 49, who was visiting Moscow from Oklahoma City. It is not certain if any of the attackers survived.

Booker's fiancee, Svetlana N. Gubareva, survived the attack. In a telephone interview with The Associated Press on Wednesday, Gubareva said she testified last week before the federal grand jury in Washington about the attack, and also spoke to FBI and Justice Department officials.

``They asked me if I knew anything about a connection between the Chechen terrorists and al-Qaida,'' Gubareva said. ``From what I saw in the room, I didn't have any facts that these people were connected with al-Qaida. None of them mentioned al-Qaida in my presence. ... Of course, that doesn't mean there wasn't a connection.''

A New York-based group called the International Foundation for Civil Liberties, which works with a Russian association of relatives and survivors of the theater attack, had arranged Gubareva's travel from Moscow, said the group's president, Alex Goldfarb.

Gubareva had made it known to the Russian group, the Association of Nord-ost, that she wanted to travel to the United States and give evidence to U.S. authorities, Goldfarb said. The association is trying to demonstrate that the deaths should not be blamed solely on the Chechen rebels but also on the Russian government, because of the Russian government's use of the deadly gas.

``We were acting to help the survivors shift the emphasis on the way the public perceives the story _ as a total act perpetrated by the Chechens,'' Goldfarb said. ``They (the survivors) allocate the blame equally, on the Chechens and the Russian government.''

The U.S. government official stressed that the criminal investigation is not focused on the Russian government but on who directed and organized the attack.

Existence of the probe first was reported Wednesday by The New York Times.

The Russians have contended that rebels seeking to break Chechnya away from Moscow are connected with al-Qaida, an assertion that the U.S. government has not been able to prove. The U.S. official said the grand jury investigation is not focused on making this link.

The United States often brings criminal charges in cases where Americans were killed abroad, including the 2000 bombing of the USS Cole destroyer in Yemen and the indictment of al-Qaida leader Osama bin Laden in the 1998 attacks on U.S. embassies in Africa.

Frequently, however, those charged are never brought to justice in the United States.

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Associated Press writers Ula Ilnitzky and Brian Friedman in New York contributed to this story.