Chief Deputy Coroner John Sullivan, of the LaPorte County (Ind.) Coroner's Office, said Wednesday that the heat probably contributed to the death of 52-year-old Harold Montgomery, the Gary (Ind.) Post-Tribune reported Thursday.
Montgomery died of heart failure Sunday in Indiana State Prison, which is not air-conditioned.
Sullivan said Montgomery, who had been serving a 22-year sentence for dealing cocaine and a 4-year sentence for possessing a handgun without markings, had suffered from a heart condition.
The coroner said the cause of death for Ricky Christmas, 26, remained under investigation Wednesday. Christmas, who was expected to be released in November after he was convicted of child molestation in 2004, died at the prison last week.
Prison spokesman Barry Nothstine said prison officials were working to keep prisoners safe during the heat wave. He said fire hydrants have been opened, bottled water has been distributed and high-risk prisoners have been moved to air-conditioned areas.