Yesterday, the NY Times revealed that the NYC Civilian Complaint Review Board, the agency that investigates complaints against the NYPD, criticized two deputy chiefs for prompting "unnecessary arrests" of protesters during the Republican Convention. Needless to say, Police Commissioner Kelly had to respond, saying that they acted properly as demonstrators didn't have a permit to protest and that the NYPD allowed thousands of people to protest without incident. The NYCCCRB letter found that deputy chiefs did not use bullhorns when shouting orders, offering that some marchers might have obeyed if they heard orders. Kelly says that some bullhorns had been used, but the NYCLU points out to the Times that there have been many complaints about unclear orders from the police (in fact, the NYCLU has two lawsuits against the city for RNC/NYPD-related incidents).
Here's the NYC Civilian Complaint Review Board website, which explains why and how one should file a complaint. There are also reports -one related to the issue of protest is this 2003 study of complaints about the police during anti-war protests (PDF). Commissioner Kelly was also pissed at the NYCCCRB for leaking the letter, claiming he only received the letter detailing the NYCCCRB's findings after getting calls from the NY Times about it - you can read a PDF of the letter here. And relive the convention from our posts during that week.