Another woman was groped this evening in Brooklyn — and cops are investigating whether its the 13th attack from a serial perv whose been terrorizing women in the area since March, authorities said.

Around 8 p.m., a woman was molested from behind while on 39th Street and Fifth Avenue in Sunset Park, the sources said.

The suspect, described as being an Hispanic male in his 20s, then fled.

Late Sunday night, a 20-year-old woman was groped on Vanderbilt Street in Windsor Terrace.