Another prisoner has died in Mississippi, pushing the state’s in-custody death count for August to 15.

Earl King Davis, 55, was pronounced dead at 12:52 p.m. on Aug. 30, 2018, at Promise Hospital in Vicksburg, according to a statement uploaded to the Mississippi Department of Corrections’ website.

Greene County coroner Ladd Pulliam confirmed Davis’s death to Mississippi Today.

Davis had been transferred to Promise Hospital of Vicksburg, where he spent more than a week, Pulliam said. He died of natural causes, according to the coroner.

Davis was halfway through a 20-year sentence for manslaughter and aggravated assault. The manner and the cause of death are pending an autopsy, per the Department of Corrections.

In a press statement released Friday afternoon, corrections commissioner Pelicia Hall said she was requesting the assistance of the Federal Bureau of Investigations and the Mississippi Department of Public Safety in investigating the deaths this month.

“While we believe that most of the reported deaths during the month of August are from illnesses or natural causes, such as cancer and heart disease, based on available information, we are seeking assistance from others outside the department in the interest of transparency,” Hall said in the statement. “My administration is committed to ensuring that all individuals in the department’s care receive appropriate medical care.”

Read the rest of Mississippi Today’s coverage of this month’s spike in prison deaths here.