New York, USA - On an unusually warm day in December 2003, three dozen men filed into the Islamic Society of Bay Ridge on Fifth Avenue in Brooklyn, kneeling on the moss-green carpet for the midday prayer.
To anyone watching, the service itself would have appeared unremarkable. But several police reports, when taken together with testimony at the recent federal trial of a Pakistani immigrant in the plot to bomb the Herald Square subway station, revealed something extraordinary about the gathering: Among the kneeling men were at least three who were working undercover for the New York Police Department.
The intense level of scrutiny in the mosque that day was, by all accounts, exceptional. But it nonetheless suggests the depth of the Police Intelligence Division's clandestine programs, developed since the Sept. 11 attack, to infiltrate mosques and Muslim gatherings around New York City to try to prevent another terrorist strike.
Several of the police reports, which were disclosed during the trial, and the testimony of several witnesses also revealed much about the department's latest tactics and about these programs that were kept secret for several years.
The defendant's lawyers and civil liberties groups have criticized the use of informers and an undercover officer at the mosque, contending that the department violated limits placed on the division by a court's 1985 consent decree, which restricted its investigation of political and religious groups. But the department rejects that claim, saying that the procedures were lawful and necessary.
After Sept. 11, intelligence and law enforcement agencies were criticized for failing to recruit Muslims who could move within circles where they could gather information to learn about terrorist threats. "Now it's five years after 9/11, and nothing has blown up, and people are saying 'Why do they have the gall to attempt to penetrate?' " said one law enforcement official who has worked closely with the department and the F.B.I.
The outcome of the terror trial in United States District Court in Brooklyn, the first since 2001 that was based on an investigation by the Police Intelligence Division rather than by the F.B.I., has been hailed by police officials as a victory and a vindication. The defendant, Shahawar Matin Siraj, 24, was convicted on Wednesday of conspiring to bomb the subway station. Some of his conversations leading up to the plot occurred in the Islamic bookstore where Mr. Siraj had worked, next door to the Bay Ridge mosque.
Two witnesses at the trial — a 50-year-old paid police informer code-named Woody and a young undercover officer — were in the mosque that December day. At that point, the bombing plot had not been hatched, and Mr. Siraj was not yet under investigation. The two men, and another informer who was in the mosque that day for unknown reasons and who played no role in the trial, were not even aware of one another at the time.
Details of the clandestine programs have emerged in large measure through their accounts, in their testimony in recent weeks and to a lesser degree in the police reports.
One section of the Intelligence Division, the Terrorist Interdiction Unit, is devoted to using informers as "listening posts" in Muslim communities. The detectives in the unit cultivate the informers, place them in various communities, oversee their work and collect and compile the information that they generate.
Despite the Police Department's broad publicity campaign to highlight its counterterrorism efforts since 9/11, the unit has seldom if ever been mentioned in news accounts.
The police would provide no details about the unit and how it operates beyond what came out at the trial. So its scope, the guidelines under which it works and its successes and failures, beyond Mr. Siraj's conviction, could not be immediately determined.
But one paid informer alone — the man who testified against Mr. Siraj — attended 575 prayer services at the Bay Ridge mosque and another mosque in Staten Island over 13 months. He provided information almost daily, sometimes twice a day, to his detective handler, who prepared more than 350 reports based largely on the visits to the mosques and the Islamic bookstore.
Documents referring to numbered cases — M3 and M24 — that appear to be focused on mosques suggest that there could be as many as two dozen such investigations, but it could not be learned whether any others bore fruit.
Another section, the Special Services Unit, oversaw the undercover Muslim detective, who moved into the Bay Ridge neighborhood in late 2002 to investigate terrorism and other crimes.
The detective was one of the three men at the mosque on that day in December 2003. He testified that while he occasionally saw one of the other men, the paid informer, Osama Eldawoody, in the area around the mosque and the bookstore and greeted him with a handshake, he never knew that Mr. Eldawoody was working for the police until after Mr. Siraj's arrest on Aug. 27, 2004.
The detective came from Bangladesh when he was 7 and was recruited from the Police Academy to work undercover among Muslims when he was 23. He testified under a pseudonym because prosecutors said he was still involved in other undercover investigations.
He testified that his instructions were "to be a member of the community," hang out with the young men there, and collect information. He was to focus, he said, partly on the Bay Ridge mosque, which he visited on his first day. He spent time in the bookstore, and with Mr. Siraj, after the young man made violent statements about suicide bombings in Israel and praised Osama bin Laden.
At the trial, Mr. Siraj's lawyers said he was entrapped by Mr. Eldawoody, contending that the older man cajoled and inflamed him to lure him into the conspiracy. They argued that because the informer told Mr. Siraj that he was part of a terrorist group that did not exist and that it would supply the explosives, no real danger existed.
Moreover, they suggested throughout the trial that the department's tactics were improper — in particular, sending informers and the undercover detective into mosques to cast a wide net in search of radical Islamists. But jurors later said they examined and rejected the entrapment defense. Mr. Siraj now faces a maximum sentence of life in prison.
On Friday, Police Commissioner Raymond W. Kelly said that the verdict "validates so much of what we've done to protect the city."
Some critics, however, suggest that by sending people undercover into mosques and neighborhoods with a broad mandate to collect intelligence, the police are sweeping up information that has nothing to do with terrorism or crime.
"The Police Department's indiscriminate monitoring of Muslim communities assures that most of its surveillance will be of lawful activity," said Christopher Dunn, the associate legal director of the New York Civil Liberties Union. "This contrasts sharply with traditional law enforcement work, which typically and rightly focuses on unlawful activity. You don't see the F.B.I. hanging out in churches and bookstores in Little Italy hoping to run into the mob, yet that's what the N.Y.P.D. is doing in Muslim communities in its search for Muslim extremists."
Mr. Siraj's lawyer, Martin R. Stolar, who had said that he intended to put the department's tactics on trial, made much the same argument in defense of his client — an argument, police officials noted, that carried little weight with the jury. He contended that the department had "presumptively violated" the 1985 consent decree governing the Intelligence Division. Mr. Stolar was one of the lawyers who brought the civil lawsuit in 1971 that led to the decree limiting the department's investigations of political and religious activity. But the judge at this trial, Nina Gershon, waved off his arguments.
Paul J. Browne, the chief spokesman for the department, said it employed the informer and the undercover officer to follow up on leads of suspected terrorist activities, as it does when it deploys undercover narcotics detectives. "In both instances, placement is dictated by the reported activity, not the community, ethnicity or religion," he said.
One counterterrorism official said the Intelligence Division operated under the close supervision of two lawyers, both former federal prosecutors, who work to ensure that everything is done according to the most stringent interpretations of the decree. During much of the Herald Square investigation, one was assigned to the city's Law Department and the other to the police deputy commissioner for legal matters, S. Andrew Schaffer, who himself attended much of the trial.
Mr. Stolar also sought to highlight what he suggested were lapses in police procedure.
For example, during Mr. Stolar's cross-examination of Mr. Eldawoody's handler, Detective Stephen Andrews of the Terrorist Interdiction Unit, he asked about problems the informer had using a small digital device to secretly record conversations with Mr. Siraj. Detective Andrews acknowledged that he was unable to instruct Mr. Eldawoody because he himself had not been trained to use the device. As a result, for six weeks, the informer was unable to make any recordings.
Mr. Browne dismissed the criticism as uninformed, saying the department had thwarted a bombing plot. "That's the reality, despite the defense's understandable but ultimately failed attempt to identify purported weaknesses in police methods and procedures," he said.
During the trial, a senior police official acknowledged that mosques had at one time been a focus of the department's efforts, but he said that investigators had significantly broadened their scope since then.
"We don't investigate mosques, we investigate people," the official said. "We're not in every mosque — that's not where we need to be. That's Intel 101. We're in the graduate program. The bad guys aren't hanging around the water cooler after Friday prayers anymore."