sfo.jpgFederal authorities were still working today to identify a caller who phoned in a hijacking threat that grounded an American Airlines flight Thursday at San Francisco International Airport.

Passengers aboard American Airlines Flight No. 24 destined for New York’s John F. Kennedy International Airport idled in their seats for hours after airport police learned of the threat.

They were eventually taken back to the airport terminal to rebook their flights.

An anonymous phone call to a desk clerk at the Hampton Inn and Suites in Alameda led the hotel’s manager to contact local police, who in turn alerted the FBI of the threat.

Although authorities determined the threat was not credible, investigators are still attempting to identify the caller who triggered the clampdown on the tarmac.

Thursday, authorities questioned all 163 passengers who were aboard the flight, but no arrests were made, FBI spokesman Joe Schadler said.

When authorities first boarded the plane, a couple seated near the plane’s rear was approached and questioned.

The man and woman were led off the plane separately and questioned, Schadler said.

The remaining passengers were later led off the front of the plane in groups of six, scanned with a wand by San Francisco police officers, and shuttled back to the terminal to rebook their travel plans.

Passenger Andrew Latham, 27, of England, was sitting two rows ahead of the pair who were removed.

He said law enforcement officers who boarded the plane spoke briefly with the man, asking him his name and where his bags were. They then led the man off the plane in handcuffs, Latham said.

“There was specific information that led to that action,” Schadler said. “That’s not something you can discount without knowing the facts.”

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