A man convicted of arson in 2013 for setting a fire outside his estranged wife's apartment complex in Medford died in prison Monday.

Louis Walls, 51, was found unresponsive in his cell at about 12:20 a.m. Monday, April 10, and died of apparent natural causes inside the Oregon State Penitentiary in Salem, according to an Oregon Department of Corrections news release. Walls was pronounced deceased at 12:55 a.m.

A Jackson County Circuit Court jury unanimously found Walls, of the 400 block of North Phoenix Road, guilty of first-degree arson. Walls entered prison Sept. 19, 2013. His earliest release date was Oct. 26, 2020.

Prosecutors argued that Walls was enraged over financial issues with this wife and the fact that she was cheating on him. Anger led Walls to set a fire outside his wife's apartment complex in the 2300 block of East Barnett Road.

Walls lit some pizza boxes on fire at a corner of the apartment building. The flames charred a small area but did not spread beyond the facade.