INDIANAPOLIS (AP) - A state prison official says Orville Lynn Majors, who was convicted of killing six people while a nurse at an Indiana hospital, has died.

Indiana Department of Correction spokesman Douglas Garrison says Majors died of natural causes Sunday at the Indiana State Prison in Michigan City.

The 56-year-old Majors was serving a 360-year sentence.

Majors was convicted in 1999 on charges he gave lethal injections of heart-stopping drugs to ailing patients at the former Vermillion County Hospital in Clinton, about 60 miles (96 kilometers) west of Indianapolis near the Indiana-Illinois state line.