Police mugshots of a reputed flasher have been posted in Widener and Lamont Libraries, where the exhibitionist has struck in recent months.
Following several incidents in June, Harvard University Police instructed library guards to be on the lookout for the man. Several students had reported seeing the young, sparsely dressed man exposing himself in the Widener stacks.
Deputy Police Chief Jack Morse said the man is "well known" to the police.
Police apprehended the flasher June 10 and charged him with "open gross conduct and trespassing."
Morse refused to release the man's name, saying it was a "sensitive case."
A University identification card is required to gain entrance to Lamont and the Widener stacks, but Morse said the man is not affiliated with Harvard. Morse said the man may have gotten past the guards by walking in a large crowd.
Shortly after the arrest, library personnel reported seeing the man in the stacks.
One worker told Barbara Allsep, assistant to the head of the stacks division, that he had just seen the exhibitionist. But by the time Allsep called the University police, the suspect had fled.
"That kind of criminal usually shows up again," Morse said.
Although flashers are not the typical library-goers, Allsep said this one is not Widener's first.
"This sort of thing hasn't happened for about two years," she said. "It used to come up quite often, especially around exam time, when the students get rather punchy."
Morse said he did not know whether man had been convicted of the charges.
"Misdemeanors don't spend much time in jail," he said. "The courts are a little lenient on them...They should maintain closer supervision so they don't act out in this fashion again."