Students said they worried the surveillance on campus could follow them after graduation or extend to their families and workplaces.

With its whitewashed bell tower, groomed lawns and Georgian-style buildings, Brooklyn College looks like a slice of 18th Century America dropped into modern-day New York City. But for years New York police have feared this bucolic setting might hide a sinister secret: the beginnings of a Muslim terrorist cell.

Investigators have been infiltrating Muslim student groups at Brooklyn College and other schools in the city, monitoring their internet activity and placing undercover agents in their ranks, police documents obtained by the Associated Press show. Legal experts say the operation may have broken a 19-year-old pact with the colleges and violated U.S. privacy laws, jeopardizing millions of dollars in federal research money and student aid.

The infiltration was part of a secret NYPD intelligence-gathering effort that put entire Muslim communities under scrutiny. Police photographed restaurants and grocery stores that cater to Muslims and built databases showing where people shopped, got their hair cut and prayed. The AP reported on the secret campaign in a series of stories beginning in August.

The majority of Islamic terrorism cases involve young men, and infiltrating student groups gave police access to that demographic. Alarmed professors and students, however, say it smacks of the FBI spying conducted on college campuses in the 1960s. They are calling on college administrators to investigate.

“It’s really about personal freedom,” said Moustafa Bayoumi, an English professor at Brooklyn College. “The government, through the police department, is working privately to destroy the private lives of Muslim citizens.”

Last week, professors at the City University of New York’s Law School issued a statement warning that the spying at CUNY campuses may have violated civil rights laws. The Brooklyn College Faculty Council has passed a similar measure.

Outside a prayer room used by their club on the edge of the Brooklyn College campus, members of the college’s Islamic Society worried they might be marked for life—flagged on a terrorism watch list or blacklisted in a police dossier—because of the surveillance.

“We come to the room, we talk, we chill,” said Shirin Akter, 20, an elementary education major. “So if another sister comes into the room and she’s a cop, that’s not cool. I’m really scared about this.”