The US government is enlisting university police departments in its war on terrorism.
University police normally carry out duties such as patrolling sprawling campuses and stopping underage student drinking. But several are working with the FBI.
The partnership became public only after an Iraqi-born professor was questioned about his loyalty to the US, even though the agency said he was not suspected of any wrongdoing.
The interrogation was conducted jointly by an FBI agent and a University of Massachusetts campus police officer. They confronted economics professor M.
J. Alhabeeb, an Iraqi-born US citizen who fled Iraq in 1982 during the Iran-Iraq war. Professor Alhabeeb said his brother-in-law was executed by Saddam Hussein's regime.
Professor Alhabeeb was questioned about his political views and affiliations.
The same university police officer later helped a federal agent question a university employee from Sri Lanka who is active as a union organiser. The FBI said the union organiser was not suspected of wrongdoing.
Civil libertarians and academics protested that involving university police in such investigations and allowing FBI agents to question faculty members about their political views was reminiscent of the anti-communist witch-hunts of the 1950s.
"We are concerned that an FBI presence on college campuses could have a chilling effect on the free speech of students, professors and other university employees," said John Reinstein, legal director of the regional office of the American Civil Liberties Union.
Civil liberties attorney Bill Newman said: "The FBI should not be investigating people based on their political views, particularly on a college campus."
The university said that its officer reported to the local office of the FBI.
Other universities confirmed that they also had campus police officers assigned to the intelligence agency. They include the universities of California, Colorado, North Carolina and Rhode Island.
At least two universities, Rutgers and Pennsylvania State, have refused to allow their campus police to serve as liaising officers with the FBI.
The civil liberties association is demanding that the FBI reveal the degree to which it is involved on university campuses. The FBI has yet to issue a response.