A 75 year old protester who was pushed to the ground by police officers last year is suing the city of Buffalo.
A video clip of Martin Gugino tumbling to the ground and striking his head on the pavement after a shove by officers went viral in June.
He was taking part in a protest against racism and police brutality.
Gugino was treated in hospital for a fractured skull.
A civil lawsuit was filed on Monday, calling the shove unlawful use of force and a violation of his right to freedom of movement.
Buffalo's mayor, the police commissioner, deputy commissioner, and officers Robert McCabe, Aaron Torgalski, and John Losi are all named in the document.
Earlier this month a grand jury decided not to indict McCabe and Torgalski for the push, but they have been suspended as an internal investigation continues.