NEW YORK (AP) — The president of the John Jay College of Criminal Justice said he is "deeply troubled" about reports that the New York Police Department sent a paid informant to spy on the school's club for Muslim students.

School President Jeremy Travis sent a letter to students and professors Thursday reacting to an Associated Press report on the 19-year-old informant, Shamiur Rahman, who said he quit working for the NYPD at the end of the summer after growing uncomfortable with the job.

Rahman said his assignments included attending lectures hosted by John Jay's Muslim Student Association, photographing people attending its events, and identifying its members and leaders.

The college, located in Manhattan, is attended by thousands of students hoping to pursue a career in law enforcement.

In the letter, Travis said he was unaware of the spying, and expressed concerns about using informants for surveillance where there was no evidence of a crime.

"Any surveillance practices that interfere with constitutionally protected activities such as free speech, freedom of association and the free exercise of religion must be considered inconsistent with the mission and values of our College," he wrote.

Police Department spokesman Paul Browne wouldn't comment on Travis' concerns. In an email Saturday, he contested only one part of the letter, in which Travis cited a recent report by another news organization that quoted Browne as confirming that Rahman had indeed been an NYPD informant. Browne denied that he had made that confirmation.

In the past, NYPD officials have repeatedly said the department only uses undercover investigators or confidential informants when it has information indicating the possibility of unlawful activity.

Addressing the college community, Travis said in his letter that "I trust that you would agree that, in certain limited circumstances it is appropriate for law enforcement agencies to use informants to uncover criminal activity. There is no evidence, however, that this is the case at John Jay and we have not been advised otherwise."

Rahman said his work as an informant began last winter, just as the AP was publishing a series of stories about the police department's use of informants and undercover investigators to monitor Muslim student groups around the northeast U.S.

Those articles prompted letters from several college presidents expressing concerns about the tactic.

Mayor Michael Bloomberg has defended the department's intelligence-gathering operation as necessary to root out any potential terrorist plots.