Halloween Night Disturbance: 5th Ave and President

does anyone happen to know why several dozen police officers and at least two ambulances -- all with sirens blaring -- converged on 5th avenue between president and carroll st. at around 8.30pm halloween night?

i overheard someone in the crowd saying that two men were fighting, the cops tried to break it up, and one of the men started fighting with the cops. but i came upon the scene about 60 seconds too late to figure it out for myself.

We saw a hit and run accident around there at about the same time. Some lady in a black Honda CRV side swiped a parked car with people in it, almost ripping off the rear left door. They offending car initially stopped, but then drove off. So if you see a 40-ish looking blonde lady with a busted right mirror on her black Honda....

well, i still dont have an answer, but at least i did get a mention on gawker:

http://gawker.com/news/anything-can-happen-on-halloween/park-slope-candy-shortage-ends-in-violent-melee-317837.php