WEST BURLINGTON, Iowa (AP) — Officials say a prisoner serving a life sentence for murder died Wednesday morning at a southeast Iowa hospital. 71-year old Everett Lyon was pronounced dead due to natural causes at 3:58 a.m. at Great River Medical Center in West Burlington. He’d been sent there for a suspected heart attack.

Lyon was convicted of first-degree murder in Marshall County. Prison records say Lyon had been serving his time at the Iowa State Penitentiary in Fort Madison. His incarceration began on April 10, 1979.