The man grabbed a 26-year-old woman from behind Sunday at 2:15 a.m. at the corner of South 4 and Havemeyer streets in Williamsburg.
She reacted by trying to slap him, at which point he punched her in the face multiple times before running off.
She suffered bruising and swelling.
The NYPD's Brooklyn Special Victims Squad is investigating.
The attacker is described as a man with a dark complexion, approximately 35-years-old, 6'0" tall, 150 pounds, with black hair and brown eyes. He was last seen wearing a dark-colored baseball hat, a du-rag, a white t-shirt with dark-colored sleeves and the number "88" on the back, denim shorts, and white sneakers.
Anyone with information in regard to this incident is asked to call the NYPD's Crime Stoppers Hotline at 1-800-577-TIPS (8477) or for Spanish, 1-888-57-PISTA (74782).
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