Authorities were investigating an alleged sexual assault Saturday evening inside a tent at Dilworth Plaza, where Occupy Philadelphia protesters have been camped out for more than a month.

A 25-year-old woman from Atlantic City called authorities about 7:45 p.m. to report a rape, Lt. Ray Evers, a Philadelphia police spokesman, said. A 50-year-old man from Michigan, who also has an address in Philadelphia, was in custody and faced charges of rape and related offenses, Evers said.

The suspect was arrested shortly after the 911 call. Authorities believe both the woman and the suspect were participants in the Occupy Philadelphia encampment, which consists of scores of tents pitched out on the plaza.