PARK SLOPE - Police are investigating an alleged sexual attack that happened on 16th Street in Park Slope, where a number of similar attacks went unsolved last year.

Witnesses say they heard the sounds of a woman screaming for help at around 5 a.m. this morning. A witness observed a 22-year-old woman struggling to get away from an attacker who allegedly was attempting to rape her. Police say the man, who appeared to be in his 40s, attempted to grope her under her skirt.

One witness says his neighbor chased the suspect for several blocks, caught him, and held him down until police arrived on the scene. Police say they let that man go because there was no witness at that scene. Neighbors say they are upset with the way police handled the situation.

Police say there is a lot of misinformation being spread concerning the details of the incident. They say are still on the hunt for the suspect.