Police are looking for the suspect in a rape at a Bronx building this week.

Around 1 a.m. Monday, a man approached a 21-year-old woman, told her he had a knife and forced her into the top-floor landing inside the stairwell at a building on Banyer Place in the Soundview section.

The victim was apparently waiting for someone else to pick her up but before the ride came, the suspect instead forced her up to the roof and raped her, according to the NYPD, then robbed her and fled. She was taken to Jacobi Hospital for evaluation.

“It seemed like somebody was in trouble, it was really frightening type of noise,” said a resident of the building, Ray Parker.

Surveillance cameras captured an image of the suspect riding a scooter before the brutal attack.

On Tuesday morning, black powder covered the walls inside the building, used by police to pick up fingerprints that they hope will help lead to an arrest.

One resident of the building opened her door at about 1 a.m. and said she locked eyes with the victim.

“The girl was being dragged from the roof area and her body was just going boom, boom, boom, down the stairs,” said the witness’s niece, Piedad Cordova. “Her clothing was ripped, she was crying, she was hurt, she was bruised up.”

The suspect is described as black, about 6 feet tall and 140 pounds with a medium complexion, black hair in braids, brown eyes and a rash on the right side of his face.

Anyone with information on the case is asked to call 1-800-577-TIPS (8477).