The family of a Brooklyn teenager is suing the NYPD, claiming an officer knocked their son out and gave him brain damage after mistaking his cigarette for marijuana.

Seventeen-year-old Marcel Hamer was reportedly walking home from school smoking a cigarette when a plainclothes officer stopped him, apparently suspecting the cigarette contained marijuana.

The stop turned into a physical confrontation, partially captured on film. Hamer's family says, in their civil suit, that the officer struck Hamer so hard he passed out. In the video, Hamer appears to be unconscious, and the teen says he's suffered headaches, dizziness and memory loss. According to Brooklyn Paper:

The moment of the apparent knockout blow is partially obscured in the footage, but the officer appears to punch Hamer in the face with his left hand, prompting protests from Hamer's friends.

Hamer was eventually charged with—and pleaded guilty to—disorderly conduct. The NYPD told reporters Internal Affairs is investigating the matter.

[h/t NYMag]