A York County Jail inmate killed himself on Sunday by removing a shunt that had been used for his kidney dialysis, according to the findings of the State Medical Examiner's Office.

Authorities say Jeffrey Noonan had told medical officials that he planned to make such an attempt, according to a news release from the Maine Department of Public Safety. He was placed on suicide watch at the jail as a result.

He was found dead Sunday morning at 6:30 a.m., just 18 minutes after he was last checked by jail personnel.