NEW YORK (AP) -- Even before it showed up in a secret police report, everybody in Bay Ridge knew that Mousa Ahmad's cafe was being watched.
Strangers loitered across the street from the cafe in this Brooklyn neighborhood. Quiet men would hang around for hours, listening to other customers. Once police raided the barber shop next door, searched through the shampoos and left. Customers started staying away for fear of ending up on a blacklist, and eventually Ahmad had to close the place.
But when asked if he would consider legal action against the police, Ahmad just shrugs.
"The police do what they want," he said, standing in front of the empty storefront where his cafe used to be. "If I went to court to sue, what do you think would happen? Things would just get worse."
It's a common sentiment among those who are considering their legal options in the wake of an Associated Press investigation into a massive New York Police Department surveillance program targeting Muslims. Many of the targets feel they have little recourse - and because privacy laws have weakened dramatically since 9/11, they may be right, legal experts say.
"It's really not clear that people can do anything if they've been subjected to unlawful surveillance anymore," said Donna Lieberman, executive director of the New York Civil Liberties Union.
The AP investigation revealed that the NYPD built databases of everyday life in Muslim neighborhoods, cataloguing where people bought their groceries, ate dinner and prayed. Plainclothes officers known as "rakers" were dispatched into ethnic communities, where they eavesdropped on conversations and wrote daily reports on what they heard, often without any allegation of criminal wrongdoing.
The NYPD did not respond to repeated requests for an interview, but it has insisted that it respects the rights of people it watches. Commissioner Ray Kelly says each request for surveillance is thoroughly examined by the department's lawyers.
"The value we place on privacy rights and other constitutional protections is part of what motivates the work of counterterrorism," Kelly told a city council committee. "It would be counterproductive in the extreme if we violated those freedoms in the course of our work to defend New York."
But critics of the surveillance say the NYPD is taking advantage of a general weakening of state and federal restraints, many of them forged during the 1960s and following the Watergate scandal:
-The USA PATRIOT Act, passed after the 9/11 attacks, reduced legal limits on wiretaps imposed by the Omnibus Crime Control and Safe Streets Act of 1968. The same law also amended the Right to Financial Privacy Act of 1978 to allow banks to release records to intelligence agencies investigating terrorism.
-A 2007 law changed the Foreign Intelligence Surveillance Act of 1978, originally a reaction to former President Richard Nixon's spying on political groups, to allow wiretaps of international phone calls.
-In 2002 the Supreme Court decision ruled that students cannot sue universities under the 1974 Federal Education Rights and Privacy Act. That could make it harder for Muslim student groups to seek redress over infiltration by NYPD undercover officers.
The U.S. Department of Justice still has some tools it can use to discipline local police forces.
It can withhold federal money from any police agency that discriminates on the basis of race, color, sex or national origin. Another law allows the Justice Department's Civil Rights Division to sue state and local police forces for any "pattern or practice" that deprives people of their Constitutional rights. In September it cited the statutes in a scathing report about corruption and abuse within the Puerto Rico Police Department.
Rep. Rush Holt, D-N.J. has asked the Justice Department to investigate the NYPD surveillance program.
But in Puerto Rico and elsewhere, the Justice Department has typically focused only on issues of excessive force, illegal traffic stops and other clear violations of police procedure. Since 9/11, the department has not used its civil rights authority against a police department in a national security case.
Lawsuits filed by surveillance targets themselves are notoriously hard to win, said Paul Chevigny, a law professor at New York University and expert on police abuse cases.
"The fact that you feel spooked and chilled by it doesn't constitute an injury," Chevigny said. Even in cases where surveillance notes leak out, the chances of winning a lawsuit are "marginal" unless the leaking was done with the clear intent of harming someone, he said.
In Ahmad's case, police documents obtained by the AP show officers were compiling a report on Moroccan neighborhoods as part of an effort to map the city's Muslim communities. Ahmad's Bay Ridge International Cafe appears with two other nearby restaurants, along with notes about their ownership, customers and size.
Neighbors were especially suspicious about one physically fit man in his 50s who would spend hours sitting on a bench outside a doughnut shop across from the cafe, said Linda Sarsour, director of the Arab-American Association of New York, which has its offices down the street.
"It's like, `Why don't you have a job, bro? Why are you always hanging out in every coffee shop?'" Sarsour said. "That was shady."
In 2009 neighbors got fed up and asked for a meeting with the commander of the local police precinct, Ahmad said. They met in Ahmad's cafe. The commander did not confirm any surveillance operation, but the strange men on street corners disappeared after that, he said.
Still, the stigma remained, Ahmad said. He changed the cafe's name, but business never recovered. Finally he sold it, but the new owner did no better and eventually closed it for good.
Over the last 40 years, there has been only one class-action lawsuit that has forced serious changes to an NYPD surveillance program, lawyers say, and those changes have been eroded since the 9/11 attacks.
In 1971, 16 leftists led by lawyer Barbara Handschu sued the police department for spying on them. In 1985 they settled the case in exchange for a set of rules, known as the Handschu Guidelines, that set up a three-member panel to oversee NYPD surveillance operations.
The rules also said detectives could only start an investigation when they had "specific information" about a future crime.
"An individual's or organization's political, religious, sexual or economic preference may not be the sole basis upon which the (police intelligence division) develops a file or index card on that individual or organization," the rules said.
In 2003 a judge agreed to relax the rules. Under the new rules, known as the Modified Handschu Guidelines, NYPD intelligence chief David Cohen can act alone to authorize investigations for a year at a time. He can also authorize undercover operations for four months at a time.
Most importantly, the rule requiring police to have "specific information" was loosened. It now says only that facts should "reasonably indicate" a future crime.
Activists say they have not ruled out going to court over the latest NYPD program. But at a "strategy meeting" held in Manhattan on Wednesday, the discussion centered on preparing for a Nov. 18 protest march and on organizing "know your rights" seminars at mosques and community centers.
Organizers believe they need to build a mass movement against the surveillance program first, so that people like Ahmad will feel more confident about coming forward and filing lawsuits, said Cyrus McGoldrick, civil rights manager for the Council on American-Islamic Relations, who ran Wednesday's meeting.
"That way if there's a court date, it's not just 10 people sitting there, it's 1,000 people outside the courthouse, every day," he said. "People need to feel there is a movement protecting them before they take on the police. Apathy is not our problem - fear is our problem."
As the 9/11 attacks recede into the past, state and federal rules may eventually swing toward privacy rights again, said Judith Berkan, a member of the advisory board of the National Police Accountability Project, a group of civil rights lawyers.
But until then, surveillance targets would likely face a difficult court battle, she said.
"I think if the government treats you different because you're from a particular part of the world, even if the surveillance is in a public place, it might violate the constitution," Berkan said. "But it's not a favorable judicial climate for me to make those kinds of arguments today."