Philadelphia ? She was a freshman at Bryn Mawr College, preparing to fly home to California for Christmas, sleep-deprived, with questions from a calculus exam still racing through her head.

In the space of a few hours on Dec. 21, 2003, Janet Lee landed in a Philadelphia jail cell, where she would remain for three weeks, held on $500,000 bail and facing 20 years in prison on drug charges. All over flour found in her luggage.

“I haven’t let myself be angry about what happened, because it would tear me apart,” Lee said. “I’m not sure I can bear to face it. : I’m amazed at how naive I was.”

That naivete, she said, began when screeners at Philadelphia International Airport inspecting her checked luggage found three condoms filled with white powder. Lee laughed and told city police they were filled with flour. It was just part of a phallic gag at a women’s college, she told them, a stress-reliever, something to squeeze while studying for exams.

The police didn’t find it funny. They told her a field test showed that the powder contained opium and cocaine.

A lab test later proved the substance was flour.

But the case returned to the courts last week as Lee filed a federal civil-rights lawsuit against city police.

The lawsuit seeks damages for pain and suffering, financial loss and emotional distress.

Capt. Benjamin Naish, a spokesman for the Police Department, declined to comment, noting that the department rarely comments on litigation. A spokeswoman for the District Attorney’s Office also declined to comment.