It happened on March 31 at 2:10 a.m. on Church Avenue in East Flatbush.
Video shows the man riding up on a scooter next to the 59-year-old victim and slapping her in the face, knocking her to the ground.
Moments after knocking her into the street, the man rides back, and that's when police say he ripped off her pants and sexually abused her.
Then, the man took off along Church Avenue.
The victim refused medical attention at the scene.
UPDATE: Police have arrested 21-year-old Omar Dasilva in connection with this incident. He is charged with sex abuse, sexual misconduct, forcible touching, and assault.
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