An immigration agent was seen on camera clapping his hands together seconds after the fatal shooting of Alex Pretti in Minneapolis on Saturday (24 January).
Mr Pretti, a 37-year-old intensive care nurse, was beaten and shot dead by Customs and Border Protection officers after a confrontation in the Twin Cities.
Officers allegedly wrestled him to the ground, beat him and apparently removed a handgun from a holster he was wearing, before firing ten shots at him.
Footage appears to show an agent, who was not involved in the shooting, clap his hands twice after gunfire rang out and as screams can be heard from onlookers.