Charges could be filed within four to six weeks in connection with the investigation of damaged O-rings made for space shuttle booster rockets, according to an FBI spokesman.

The investigation centers on O-rings produced by HydraPak, a West Jordan manufacturing company that supplies the rings to Morton Thiokol. Morton Thiokol uses the rings in the rocket booster engines it supplies for the U.S. space shuttle. A faulty motor design involving O-rings has been blamed for the explosion that killed seven astronauts aboard the shuttle Challenger in 1986.Cal Clegg, media spokesman for the Salt Lake FBI office, said the investigation has eliminated the possibility that the apparent sabotage to the O-rings was influenced by countries hostile to the United States or by internal struggles affecting local polygamist groups.

Clegg said he erroneously indicated that arrests in the case were imminent. He said that while the investigation is moving in a positive direction, he said it will likely be four to six weeks before it is complete. He said it will then be up to the U.S. attorney to determine whether charges will be filed.

He said the investigation is focusing on one or more people.

"We don't want to say exactly who is being investigated at this time," Clegg said.

HydraPak reported finding O-rings with razor cuts during an inspection in August. The findings were immediately reported to Morton Thiokol and NASA. Company officials say it appears no damaged O-rings were shipped.