The Zearing man who authorities say killed his wife in the couple’s home last week was formally charged Thursday with first-degree murder.

Gary Pillman, 70, was arrested on Nov. 13, on a charge of second-degree murder after he went to a neighbor’s house, where he said he stabbed his wife and then tried to kill himself.

Story County Attorney Jessica Reynolds declined to comment on the reason for filing the more serious charge citing the pending prosecution.

Pillman is scheduled to be arraigned in Story County District Court in Nevada at 1 p.m. on Monday, Dec. 2.

If convicted of first-degree murder, Pillman would face life in prison without parole. Second-degree murder is punishable by up to 50 years in prison, with a mandatory minimum sentence of 35 years before becoming eligible for parole.

Pillman, a former superintendent and principal in the Colo-NESCO school district, made his initial court appearance on Nov. 14. He remained held in the Story County jail on Thursday on $500,000 bond.

Pillman is accused of stabbing his wife Betty, 62, who was found dead in the front yard of the couple’s home in Zearing, a town of about 500 people in rural northeastern Story County. Authorities said Betty Pillman “suffered severe lacerations to her upper body.”

Gary Pillman’s cuts to his arm were not considered life-threatening, but he was taken to Mary Greeley Medical Center in Ames, where he was treated for the cuts, which authorities said were self-inflicted.