Police are looking for a woman who was seen mumbling to herself before she allegedly pushed an unsuspecting man to his death in front of an oncoming No. 7 train at a Queens subway station Thursday evening, police said.

The man was standing on the northbound platform of the 40th Street and Queens Boulevard elevated train when police say the woman walked up behind him and pushed him onto the tracks. Witnesses told police the man had his back to the woman and didn’t appear to notice her. No words were exchanged.

The man died at the scene. His identity has not been released.

Witnesses told police the female suspect had been walking back and forth on the platform and talking to herself before sitting down, alone, on a wooden bench near the north end of the walkway. When the train pulled into the station shortly after 8 p.m., the woman got up off the bench and pushed the man, according to witness statements.

The suspect then fled the platform, running down a flight of stairs to the turnstile area and down a second flight to Queens Boulevard. It’s unknown where she went from there. Police released surveillance video of her running onto the street.

The suspect is described as being a heavyset woman about 5 feet 5 inches tall with brown or blond hair. She was wearing a white and gray ski jacket and Nike sneakers at the time of the incident.

It is the second time this month that a person has been shoved onto subway train tracks and killed.

Naeem Davis, a 30-year-old deli worker, was recently arrested and charged with second-degree murder for allegedly pushing a man off a midtown subway platform to his death.

Ki-Suk Han, 58, was stuck by a southbound Q train after being pushed off the platform at the 49th Street station in Manhattan Dec. 3.

(Source: NBC New York)