Corrections officials in Georgia say they’re investigating an apparent inmate suicide by a man serving a life sentence for a Hall County murder.

The Department of Corrections said in a news release that prison guards found Hugo Tepanca unresponsive in his cell at around 4:25 a.m. Tuesday. The agency said prison medical staff performed CPR, and the prison medical director pronounced Tepanca dead around 4:45 a.m.

Corrections officials said they are investigating the death.

Tepanca was serving a life sentence for a murder conviction in Hall County in the April 2008 fatal shooting of Jose Sanchez-Vargas. Prosecutors said Tepanca shot the man six times on Merck Street in Gainesville. Tepanca claimed he believed his girlfriend was having an affair with Sanchez-Vargas.

Tepanca was convicted on all charged in April 2010 and sentenced to a life prison sentence for felony murder.

Tepanca’s attorney said in the January 2015  appeal to the Georgia Supreme Court that the jurors should have been instructed on adultery as a provocation for manslaughter as well as an instruction on “mutual combat,” which could have been considered manslaughter instead of murder.

The district attorney’s office challenged this assertion in the appeal, saying there was no evidence of adultery nor mutual combat.

The Georgia Supreme Court upheld his conviction in 2015.

The Associated Press contributed to this report.