The ACLU has filed a lawsuit on behalf of a college student who was arrested by the TSA and detained for five hours over a set of Arabic-language flash cards he was carrying.

Nick George, a student at Pomona College in California, was grilled by the TSA on "who did 9/11" and asked by FBI agents whether he was a communist after airport security officers found Arabic-English language learning cards in his luggage last summer, according to news reports and the ACLU.

George was boarding a plane to California on Aug. 29, 2009, after visiting his native Pennsylvania when TSA agents noticed the cards. George had been studying Arabic and used the flash cards -- which have Arabic on one side and English on the other -- to help him translate the Arabic news service al-Jazeera. Among the flash cards were the words "terrorist" and "explosion," the Philadelphia Daily News reported.

Among the questions a TSA agent asked him were "Do you know who did 9/11?" and "Do you know what language Osama bin Laden spoke?"

Grilled later by the FBI, George -- who is not Arabic -- was asked if he had converted to Islam or joined a communist organization, the Daily News reported.

"I understand I might warrant a second look," George told the paper. "They should have taken me aside, seen I had a legitimate explanation and a student ID and that I was carrying nothing illegal, and waved me on."

"Nick George was handcuffed, locked in a cell for hours and questioned about 9/11 simply because he has chosen to study Arabic, a language that is spoken by hundreds of millions of people around the world," ACLU attorney Ben Wizner said in a statement. "This sort of harassment of innocent travelers is a waste of time and a violation of the Constitution."

Wizner said that "arresting and restraining passengers who pose no threat to flight safety and are not breaking any law not only violates people's rights, but it won't make us any safer."

The ACLU says George was "never informed of why he was handcuffed, detained or arrested, and he was not informed of his rights."

The lawsuit charges that the TSA officials, the Philadelphia police and the FBI violated George's Fourth Amendment right to be free from unreasonable seizure and his First Amendment right to free speech. The ACLU filed the lawsuit on George's behalf in the U.S. District Court for the Eastern District of Pennsylvania, against the three TSA officers, two FBI agents and two members of the Philadelphia Police Department who were involved in his detainment and interrogation.

In September, Fox News reported that the TSA defended its decision to detain George. The agency said George had been flagged for inspection even before he arrived at the security gate because he was "acting suspiciously."

And during the questioning, George's "behavior escalated to a point where our officers deemed it necessary to contact the Philadelphia Police Department," a TSA spokesman told the news network.

"As someone who travels by plane, I want TSA agents to do their job to keep flights safe," George says. "But I don't understand how locking me up and harassing me just because I was carrying the flashcards made anybody safer. No one should be treated like a criminal for simply learning one of the most widely-spoken languages in the world."

The following video was uploaded to YouTube by the ACLU, Feb. 9, 2010.