NEW YORK: From an office on the Brooklyn waterfront in the months after the Sept. 11, 2001, terrorist attacks, New York Police Department officials and a veteran CIA officer built an intelligence-gathering program with an ambitious goal: to map the region's ethnic communities and dispatch teams of undercover officers to keep tabs on where Muslims shopped, ate and prayed.

The program was known as the Demographics Unit and, though the NYPD denies its existence, the squad maintained a long list of "ancestries of interest" and received daily reports on life in Muslim neighborhoods, according to documents obtained by The Associated Press.

The documents offer a rare glimpse into an intelligence program shaped and steered by a CIA officer. It was an unusual partnership, one that occasionally blurred the line between domestic and foreign spying. The CIA is prohibited from gathering intelligence inside the US

Undercover police officers, known as rakers, visited Islamic bookstores and cafes, businesses and clubs. Police looked for businesses that attracted certain minorities, such as taxi companies hiring Pakistanis. They were told to monitor current events, keep an eye on community bulletin boards inside houses of worship and look for "hot spots" of trouble.

The Demographics Unit, a team of 16 officers speaking at least five languages, is the only squad of its kind known to be operating in the country.

Using census information and government databases, the NYPD mapped ethnic neighborhoods in New York, New Jersey and Connecticut. Rakers then visited local businesses, chatting up store owners to determine their ethnicity and gauge their sentiment, the documents show. They played cricket and eavesdropped in the city's ethnic cafes and clubs.

When the CIA would launch drone attacks in Pakistan, the NYPD would dispatch rakers to Pakistani neighborhoods to listen for angry rhetoric and anti-American comments, current and former officials involved in the program said.

The rakers were looking for indicators of terrorism and criminal activity, the documents show, but they also kept their eyes peeled for other common neighborhood sites such as religious schools and community centers.

The focus was on a list of 28 countries that, along with "American Black Muslim," were considered "ancestries of interest." Nearly all were Muslim countries.

Mayor Michael Bloomberg said last week that the NYPD does not take religion into account in its policing. The inclusion of American black Muslims on the list of ancestries of interest suggests that religion was at least a consideration. On Wednesday, Bloomberg's office referred questions to the police department.

How law enforcement agencies, both local and federal, can stay ahead of Islamic terrorists without using racial profiling techniques has been hotly debated since 9/11. Singling out minorities for extra scrutiny without evidence of wrongdoing has been criticized as discriminatory. Not focusing on Muslim neighborhoods has been equally criticized as political correctness run amok. The documents describe how the nation's largest police force has come down on that issue.

NYPD spokesman Paul Browne said the department only follows leads and does not simply trawl communities.

"We do not employ undercovers or confidential informants unless there is information indicating the possibility of unlawful activity," Browne wrote in an email to the AP.

That issue has legal significance. The NYPD says it follows the same guidelines as the FBI, which cannot use undercover agents to monitor communities without first receiving an allegation or indication of criminal activity.

Before The Associated Press revealed the existence of the Demographics Unit last week, Browne said neither the Demographics Unit nor the term "rakers" exist. Both are contained in the documents obtained by the AP.

An NYPD presentation, delivered inside the department, described the mission and makeup of the Demographics Unit. And a police memorandum from 2006 described an NYPD supervisor rebuking an undercover detective for not doing a good enough job reporting on community events and "rhetoric heard in cafes and hotspot locations."

At least one lawyer inside the police department has raised concerns about the Demographics Unit, current and former officials told the AP. Because of those concerns, the officials said, the information gathered from the unit is kept on a computer at the Brooklyn Army Terminal, not in the department's normal intelligence database. The officials spoke on condition of anonymity because they were not authorized to discuss the intelligence programs.

The AP independently authenticated the NYPD presentation through an interview with an official who sat through it and by reviewing electronic data embedded in the file. A former official who had not seen the presentation said the content of the presentation was correct. For the internal memo, the AP verified the names and locations mentioned in the document, and the content is consistent with a program described by numerous current and former officials.

In the two years following the 9/11 attacks, the NYPD Intelligence Division had an unusual partnership with Lawrence Sanchez, a respected veteran CIA officer who was dispatched to New York. Officials said he was instrumental in creating programs such as the Demographics Unit and met regularly with unit supervisors to guide the effort, all while on the CIA's payroll.

Both the NYPD and CIA have said the agency is not involved in domestic spying. A US official familiar with the NYPD-CIA partnership described Sanchez's time in New York as a unique assignment created in the wake of the 9/11 attacks.

After a two-year CIA rotation in New York, Sanchez took a leave of absence, came off the agency's payroll and became the NYPD's second-ranking intelligence official. He formally left the agency in 2007 and stayed with the NYPD until last year.

Recently, the CIA dispatched another officer to work in the Intelligence Division as an assistant to Deputy Commissioner David Cohen. Officials described the assignment as a management sabbatical and said the officer's job is much different from what Sanchez was doing. Police and the CIA said it's the kind of counterterrorism collaboration Americans expect.

The NYPD Intelligence Division has unquestionably been essential to the city's best counterterrorism successes, including the thwarted plot to bomb the subway system in 2004. Undercover officers also helped lead to the guilty plea of two men arrested on their way to receive terrorism training in Somalia.

"We throw 1,200 police officers into the fight every day to make sure the same people or similarly inspired people who killed 3,000 New Yorkers a decade ago don't come back and do it again," Browne said earlier this month when asked about the NYPD's intelligence tactics.

Rep. Yvette Clarke, a Democrat who represents much of Brooklyn and sits on the House Homeland Security Committee, said the NYPD can protect the city without singling out specific ethnic and religious groups. She joined Muslim organizations in calling for a Justice Department investigation into the NYPD Intelligence Division. The department said it would review the request for an investigation.

Clarke acknowledged that the 2001 terrorist attacks made Americans more willing to accept aggressive tactics, particularly involving Muslims. But she said Americans would be outraged if police infiltrated Baptist churches looking for evangelical Christian extremists.

"There were those who, during World War II, said, 'Good, I'm glad they're interning all the Japanese-Americans who are living here,'" Clarke said. "But we look back on that period with disdain."