The victim was cleaning a public bathroom when a man rushed in and attacked her.
It happened at St. Andrew's Playground in the Bedford-Stuyvesant section around 9 a.m. Thursday morning.
"I think if we had heard her screaming a lot of us would have gone over there. I'm not the only guy that feels that way. We try to keep a safe neighborhood," said Robert Shaw, an eyewitness.
Police say a 29-year-old Parks Department employee couldn't cry out because her rapist covered her mouth.
As Robert Shaw played basketball at St. Andrews Playground in Bedford-Stuyvesant, he watched a crime scene go up around him, with white and blue tape, a swarm of officers, and an innocent victim.
"I seen her coming out on the stretcher, she was over there, all bloodied up. The police came. The ambulance came," Shaw said.
As the custodial worker started her shift, police say the suspect approached her from behind in a utility closet near the restrooms and closed the door behind him.
He started to beat hit her, and pulled out either a knife or box cutter, and then raped her.
Sources say this park employee stopped the rape when they knocked on the door twice, and startled the rapist, who then opened the door and fled on a bike.