New York, New York - A former New York state prison guard has been found guilty of murder and manslaughter in the beating death of an incarcerated Black man in December, local authorities said Monday, in a case that sparked mass public outrage.

Two officers who stood trial for the same charges were acquitted, while five others pleaded guilty to manslaughter before the trial.

A ninth man is due to stand trial in January, while a 10th pleaded guilty to lesser charges.

David Kingsley, the convicted former state corrections officer, was found guilty of second-degree murder and first-degree manslaughter. He is to be sentenced on December 16 and faces up to 25 years in prison.

Robert Brooks (43) died overnight December 9-10, hours after being beaten while in handcuffs at the Marcy Correctional Facility, a prison in upstate New York.

The beating was caught on body-camera footage.

The images, released by New York Attorney General Letitia James, show Brooks, his face covered in blood, being repeatedly struck while he appears to be restrained on an infirmary bed, surrounded by at least six men.

As Brooks sits up, visibly wounded, an officer puts on a surgical glove and grabs him again by the collar and, with the help of a colleague, slams him against a wall.

The accused acted with "depraved indifference to human life, recklessly engaged in conduct which created a grave risk of death to another person, and thereby caused the death of Robert Brooks," said the indictment issued by special prosecutor William Fitzpatrick.

Brooks was serving a 12-year sentence for assault. His death was ruled a homicide.

The two other officers who risked a trial, Matthew Galliher and Nicholas Kieffer, faced the same charges as Kingsley but were acquitted.