Story highlights NYPD started the Demographics Unit after 9/11 and monitored Muslim business, mosques

The department disbanded the group, saying outreach could yield the same the information

Advocacy groups that filed suit welcomed the decision but remain vigilant about spying

A controversial New York Police Department surveillance unit that cataloged information on Muslim communities has been disbanded, according to the department.

The NYPD's Demographics Unit -- or Zone Assessment Unit -- was developed with the CIA's help after the September 11, 2001, attacks. The unit has acknowledged that it engaged in monitoring that included Muslim-owned business and mosques across the New York region and has been the target of controversy and civil lawsuits.

"The Zone Assessment Unit, previously referred to as the demographics unit, has been largely inactive since January," the department said in a statement Tuesday. "Recently, as part of an ongoing assessment of Intelligence Bureau operations, personnel assigned to the Zone Assessment Unit were reassigned to other duties within the Intelligence Bureau."

The statement continued: "Understanding certain local demographics can be a useful factor when assessing information regarding potential threats coming to the attention of the New York City Police Department, it has been determined that much of the same information previously gathered by the Zone Assessment Unit may be obtained through direct outreach by the NYPD to the communities concerned."

Two advocacy groups that filed a lawsuit challenging the unit and its activities said they were pleased it had been disbanded but want to ensure the surveillance stops.

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"While we welcome the dismantling of the Demographics Unit as a long overdue step towards reining in the unconstitutional excesses of the NYPD, what has to stop is the practice of suspicion-less surveillance of Muslim communities, not just the unit assigned to do it," said a joint statement by Muslim Advocates and the Center for Constitutional Rights, which filed the lawsuit in 2012. "We will continue to work, through litigation and advocacy, to ensure the NYPD is fully and finally respecting the rights of the Muslim community."

That suit, Hassan v. City of New York, was dismissed in February and is currently under appeal.

The New York chapter of the Council on American-Islamic Relations echoed those sentiments.

"This is an important first step. However, the damage of unconstitutional mass spying on people solely on the basis of their religion has already been carried out and must be addressed," said Board President Ryan Mahoney.

This decision and the city's move to drop an appeal of a federal judge's August ruling that the controversial stop-and-frisk practice violated the Constitution are seen as signs of changes in the way the city operates. Mayor Bill de Blasio and Police Commissioner William Bratton have replaced former Mayor Mike Bloomberg and former Commissioner Ray Kelly.

"Our administration has promised the people of New York a police force that keeps our city safe, but that is also respectful and fair. This reform is a critical step forward in easing tensions between the police and the communities they serve, so that our cops and our citizens can help one another go after the real bad guys," de Blasio said in a statement Tuesday.

Bratton, who was police commissioner in the 1990s, once again took the helm of the nation's largest police department in December at a time of low crime rates but heightened tension with the public over his predecessor's controversial policies.

When Bratton was introduced as New York City police commissioner, he talked about bringing the police and the public "together in a collaboration of mutual respect and mutual trust."

"I will get it right again in New York City," Bratton said.