Law enforcement in the US state of New York on Friday released “devastating” footage of prison guardsbeating a black inmate shortly before he died.

The body-worn camera footage, recorded the night of December 9, shows Robert Brooks, 43, being brutalised by multiple prison guards, with his face bloodied and neck held.

Brooks, an inmate at a northern New York prison serving a 12-year sentence for assault, was pronounced dead later that night.

Letitia James, attorney-general of New York, said the video was released to provide “transparency and accountability”.

In a statement, Brooks’ relatives said “watching the horrific and violent final moments of Robert’s life was devastating for his loved ones”.

“We will not rest until we have secured justice for Robert’s memory,” the statement added.

The footage shows a handcuffed Brooks restrained on what appears to be a hospital bed, with several guards holding him down and beating him.

Brooks is later seen sitting up and then gets dragged off the bed by his collar.

A preliminary autopsy reported in local press said the cause of death was “asphyxia due to compression of the neck”, though full autopsy results remain pending.

The footage lacks audio, which James said was because the guards “did not activate” their body-worn cameras despite them being on, leading to the soundless recording.

New York governor Kathy Hochul condemned the incident in a statement.

“We have no tolerance for individuals who cross the line, break the law and engage in unnecessary violence or targeted abuse,” she said.

She has called for the 14 individuals who were involved in the fatal attack to be fired.