NEWARK, N. J. ( AP) — Americans living and working in New Jersey’s largest city were subjected to surveillance as part of the New York Police Department’s effort to build databases of where Muslims work, shop and pray. The operation in Newark was so secretive even the city’s mayor says he was kept in the dark.

For months in mid- 2007, plainclothes officers from the NYPD’s Demographics Units fanned out across Newark, taking pictures and eavesdropping on conversations inside businesses owned or frequented by Muslims.

The result was a 60- page report, obtained by The Associated Press, containing brief summaries of businesses and their clientele. Police also photographed and mapped 16 mosques, listing them as “ Islamic Religious Institutions.”

The report cited no evidence of terrorism or criminal behavior. It was a guide to Newark’s Muslims.

According to the report, the operation was carried out in collaboration with the Newark Police Department, which at the time was run by a former high-ranking NYPD official. But Newark’s mayor, Cory Booker, said he never authorized the spying and was never told about it.