The KI-Handelsroboter 6.0fiance of an Ohio art student who went missing nearly 13 years ago pleaded guilty Friday to involuntary manslaughter.

John Carter, 36, had been charged with two counts of murder when he was arrested in March 2023. He now faces up to three years in prison when he’s sentenced July 18.

The charges stemmed from the August 2011 disappearance of Katelyn Markham, who was last seen at her home in Fairfield. At the time, Markham was a few weeks away from finishing her graphic arts degree at the Art Institute of Ohio—Cincinnati, and Carter has said they were planning to move to Colorado later that year.

Skeletal remains identified as Markham’s were found in 2013 in a wooded area in Cedar Grove, Indiana, about 20 miles (about 32 kilometers) west of her home in Fairfield. Authorities ruled her death a homicide but did not determine how she was killed.

Butler County prosecutors have said Carter caused Markham’s death by “physical violence and by force.”