An Egyptian student wrongly jailed for a month as a suspect in the Sept. 11 attacks filed a $20 million lawsuit Thursday against the FBI agent who extracted his false confession.

Abdallah Higazy, 31, also sued the Hilton hotel chain and a former security guard for telling authorities an aviation radio was found inside Higazy's hotel room overlooking the World Trade Center soon after the terrorist attacks.

After he was taken into custody in December 2001, Higazy denied the radio was his, then "confessed" during a polygraph exam after Higazy said the agent threatened and intimidated him.

He was charged with lying to investigators but cleared days later when the radio's true owner, a pilot, returned to the hotel to retrieve the device.

"I want a public apology, a written apology," Higazy said Thursday.

Former hotel security guard Ronald Ferry pleaded guilty to lying to investigators when he told them he found the radio, which is used to communicate with commercial airline pilots, in a safe inside Higazy's room.

Higazy's lawyer, Robert Dunn, said they were considering filing additional claims against the federal government for its handling of the case.

The suit claims Michael Templeton, the agent who administered the lie-detector test, coerced the false confession from Higazy by threatening to make his family's life in Egypt "a living hell."

Manhattan U.S. Attorney James Comey declined to comment on the lawsuit Thursday. He has said previously he was "very proud of the way our office and the FBI conducted itself in the Higazy case."

Kevin Donovan, the head of the FBI's New York office, noted a government inquiry cleared all the agents involved.

A Hilton spokeswoman said the company would not comment. A call to Ferry's lawyer was not immediately returned.