STERLING, Colo. -

The head of Colorado's prison system wants an in depth review of the Sterling Correctional Facility following the killing of an inmate there this week.

KUSA-TV reports that Cody Gray's death was the sixth homicide in the prison, the state's largest, since 2010. He was serving a life sentence for convictions in Mesa County on charges including sexual assault, drug abuse and burglary.

The executive director of the Colorado Department of Corrections, Rick Raemisch, told the station that he wants to look beyond who did what to Gray in this case and look at how the prison operates, including how prisoners are classified. His predecessor, Tom Clements, also ordered a review of the prison in 2011.