Robert Brooks Fatal Beating Case Being Reviewed by the FBI

The fatal beating of Robert Brooks -- which was captured on horrifying body cam video from NYC corrections officers -- is being investigated by the FBI, TMZ has learned.

The federal agency said in a statement to TMZ ... “The FBI Albany Field Office and the Department of Justice are reviewing the facts and circumstances surrounding the death of Robert L. Brooks to determine the appropriate federal response. As this is an ongoing review, we are not able to comment further at this time.”

The major development comes one day after body cam footage of corrections officers brutally beating a restrained Brooks -- who died hours later -- was released by the New York State Attorney General ... showing officers hitting the bloodied man repeatedly.

The shocking video shows Robert Brooks -- an inmate serving a 12-year sentence for first-degree assault -- repeatedly being punched and kicked ... and, one man appears to gag him with a towel.

Footage also shows one officer repeatedly striking Brooks in his midsection with a shoe as other officers hold him down with his arms behind him. At one point, the officers lift Brooks up by his neck ... he's got blood all over his face and he can't even hold up his own weight.

Elizabeth Mazur, attorney for the family of Robert Brooks said on a statement to TMZ ...

“With the Attorney General’s release of these videos, members of the public can now view for themselves the horrific and extreme nature of the deadly attack on Robert L. Brooks. As viewers can see, Mr. Brooks was fatally, violently beaten by a group of officers whose job was to keep him safe. He deserved to live, and everyone else living in Marcy Correctional Facility deserves to know they do not have to live in fear of violence at the hands of prison staff.”

The results of Brooks' autopsy have yet to be released by Onondaga County Medical Examiner's Office.

We reached out to the corner's office on Saturday for any update on the case ... so far, no word back.