Working inside the New York Police Department is one of the CIA's most experienced clandestine operatives. He arrived in July as the special assistant to the deputy commissioner of intelligence. While his title is clear, his job responsibilities are not. Federal and city officials have offered differing explanations for why this top CIA officer was assigned to a municipal police department. The CIA is prohibited from spying domestically, and its unusual partnership with the NYPD has troubled top lawmakers and prompted an internal investigation. The last time a CIA officer worked so closely with the NYPD, beginning in the months after the 9/11 attacks, he became the architect of aggressive police programs that monitored Muslim neighborhoods. With that earlier help from this CIA official, the police put entire communities under a microscope based on ethnicity rather than allegations of wrongdoing. On Monday, New York Mayor Michael Bloomberg defended the arrangement. If the CIA can help us I'm all for getting any information they have and then letting the police department use it," he said. All of this has troubled lawmakers, including Sen. Dianne Feinstein, D-Calif., the chairwoman of the Senate Intelligence Committee, who has said the CIA has "no business or authority in domestic spying, or in advising the NYPD how to conduct local surveillance."