TUCSON, Ariz. (AP) — The Arizona Department of Corrections says it's investigating as a homicide the death of an inmate after he was stabbed in an attack by another inmate.

The department says Richard Curley, 53, died Saturday at Banner University Medical Center South Campus from injuries he suffered in the attack earlier that day at the Arizona State Prison Complex in Tucson.

Officers and medical responders tried to save his life after they found him with multiple stab wounds. The department says Curley was taken by paramedics to the hospital, where doctors pronounced him dead.

The department says investigators have identified the inmate who is suspected to be responsible for the attack. Investigators are interviewing witnesses.

The department says Curley had been in the state prison system since 1998, after he was sentenced in Maricopa County to serve 70 years in prison for two counts of attempted second-degree murder.