Christopher Sepulvado, 81, was scheduled to die by nitrogen gas in March. His death by natural causes compels America to grapple with the graying of its death row population.

He died at the Louisiana State Penitentiary in Angola, located in the eastern part of the state. Lawyers for Sepulvado in a statement announcing his death said he suffered from severe physical and mental decline in recent years.

Christopher Sepulvado, 81, died Saturday at the Louisiana State Penitentiary in Angola, Louisiana, "from natural causes as a result of complications arising from his pre-existing medical conditions," according to the Louisiana Department of Public Safety and Corrections.