LOS ANGELES — A college student who says he was detained at a Philadelphia airport because he was carrying English-Arabic flashcards fi led a federal lawsuit Wednesday against employees of the Transportation Security Administration, the FBI and the Philadelphia Police Department, according to the American Civil Liberties Union.

Nicholas George, a senior majoring in physics and Middle Eastern studies at Pomona College in Claremont, Calif., was returning to California from Philadelphia in August when he was randomly selected for extra screening at Philadelphia International Airport, the lawsuit filed in U.S. District Court in Philadelphia states.

When George emptied his pockets, he took out the flashcards.

Authorities detained him in the screening area for 30 minutes before he was questioned by a TSA supervisor, the lawsuit states. At one point, the supervisor asked George if he knew who committed the 9/11 terrorist attacks, according to the lawsuit.

George answered, “Osama bin Laden.”

“Do you know what language he spoke?” the supervisor asked, according to the document.

“Arabic,” George answered.

The supervisor then held up the flashcards and said, “Do you see why these cards are suspicious?”

George said he was handcuffed and held for almost five hours, during which time he was questioned by two FBI agents, who asked if George was “Islamic” or a member of a “communist group,” according to the complaint.

One of the agents concluded that George, 22, was “not a real threat,” the lawsuit states.

“I don’t understand how locking me up and harassing me just because I was carrying the flashcards made anybody safer,” George said in statement released by the ACLU.

TSA spokeswoman Ann Davis said she could not comment on pending litigation.

• Raja Abdulrahim