Today's must-read is an investigative piece by Associated Press into troubling undercover operations being used by the New York Police Department to monitor activities in the Muslim community. 

A months-long investigation by The Associated Press has revealed that the NYPD operates far outside its borders and targets ethnic communities in ways that would run afoul of civil liberties rules if practiced by the federal government.

Police have also used informants, known as "mosque crawlers," to monitor sermons, even when there's no evidence of wrongdoing. NYPD officials have scrutinized imams and gathered intelligence on cab drivers and food cart vendors, jobs often done by Muslims.

Even the FBI stays away from parts of the NYPD operation:

Valerie Caproni, the FBI's general counsel, would not discuss the NYPD's programs but said FBI informants can't troll mosques looking for leads. Such operations are reviewed for civil liberties concerns, she said.

"If you're sending an informant into a mosque when there is no evidence of wrongdoing, that's a very high-risk thing to do," Caproni said. "You're running right up against core constitutional rights. You're talking about freedom of religion."

That's why senior FBI officials in New York ordered their own agents not to accept any reports from the NYPD's mosque crawlers, two retired agents said.