A 90-year-old woman was knocked to the sidewalk when a stranger slams a trash-filled baby crib at her in an unprovoked caught-on-video attack in Brooklyn, cops said Thursday.

The nonagenarian was walking along Brighton Beach Ave. when the attacker comes down the stairs from the elevated Brighton Beach subway station above her about 9:45 a.m. Monday, video obtained by News 12 Brooklyn shows.

The brute runs in the victim’s direction, grabs a discarded baby crib on the sidewalk near Brighton 5th St. and swings it into her before running off. The impact sent the victim flying to the sidewalk, where she landed on her side as trash scattered behind her.

Two women passing by stopped to help the victim and medics later brought her to Coney Island Hospital, where she was in stable condition.

Cops released a surveillance photo of the suspect and are asking the public’s help identifying him and tracking him down. He was wearing a blue hoodie, black pants and white sneakers.

Anyone with information is asked to call Crime Stoppers at (800) 577-TIPS. All calls will be kept confidential.