CHILLICOTHE, Ohio (AP) — Ohio officials say a twice convicted murderer whose November execution was halted when a vein couldn’t be found to administer execution drugs has died of natural causes.

A spokeswoman for the Ohio Department of Rehabilitation and Correction says 69-year-old Alva Campbell was found unresponsive in his cell Saturday at a prison in Chillicothe and was pronounced dead at a hospital just before 5:30 a.m.

A federal appeals court last month denied a challenge by Campbell’s attorneys that Ohio’s three-drug execution protocol poses an unacceptable risk of pain and suffering.

Franklin County Prosecutor Ron O’Brien said Saturday on Twitter that Campbell "successfully ran out the clock after 20 years of frivolous post-conviction litigation."

Campbell was sentenced to die in 1998 for killing an 18-year-old man during a carjacking.