BRISTOL, Va. (AP) -- The mother of an inmate who died after another prisoner attacked him is suing the state for $3.5 million.

The lawsuit claims guards at Red Onion State Prison didn't respond to Kawaski Bass' pleas for help. It also says the state failed to adequately train or supervise employees responsible for maintaining safety within the housing unit where Bass was attacked.

The Bristol Herald-Courier reports that the lawsuit was filed last month in Hampton Circuit Court on behalf of Bass' mother, Deborah Delaware.

Virginia Department of Corrections spokesman Larry Traylor says the agency doesn't comment on pending litigation.

The department has said Bass was attacked in a cell at the Wise County prison on Sept. 6, 2011. He died early the next morning at a hospital in Roanoke.