A man convicted of killing a Putnam County sheriff’s deputy in 1989 has died in prison. 61-year old Robert Gray was an inmate at Mount Olive in Fayette County, and was pronounced dead of natural causes early Wednesday morning. Gray was sentenced to life in prison in 1990 and was denied parole multiple times. He was convicted of first-degree murder in the death of Deputy John Janey, who was off-duty and staking out a home for an insurance company when he was fatally shot. The Office of the Chief Medical Examiner was notified of Gray’s death.