Detectives in Brooklyn are on the hunt for a rapist who attacked a 12-year-old girl on Thursday evening after following her into her East Williamsburg apartment building, authorities said.

The NYPD released a photo Friday afternoon of the alleged perverted perpetrator sought for the attack, which occurred in the vicinity of Morgan Avenue and Skillman Avenue at about 5:45 p.m. on Nov. 6.

Based on a preliminary investigation, police believe the victim was followed into her East Williamsburg apartment building. Cops said the yet-to-be identified suspect grabbed the 12-year-old before pushing her to the ground and “forcibly” raping her in the building’s lobby.

Following the attack, cops said, the perpetrator fled the scene on foot in an unknown direction.

The incident was reported to the 9

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