The Maine Department of Corrections has named the York County Jail administrator as the next warden of the Maine State Prison.

Nathan Thayer has served as jail administrator in York County for the last three years, according to a news release from the Department of Corrections, and will start his new position Monday.

The department announced Friday that Thayer had been selected as warden of the state’s largest prison in Warren following an extensive search and selection process.

He started his career in corrections in 2006 at the Maine Correctional Center, where he served in multiple leadership positions, including as the director of security.

“We are extremely excited to have Mr. Thayer return to our team as the new warden at Maine State Prison,” Department of Corrections Commissioner Randall Liberty said in the release. “His demonstrated record of leadership and experience make me confident that he’ll be a great fit for the position.”

Thayer’s appointment follows an investigation into alleged misconduct by and among employees at the Maine State Prison that the department first became aware of in August.

Former Warden Matthew Magnusson was replaced by an interim warden in February amid the investigation into allegations of harassment, hazing and retaliation among employees along with misconduct related to inappropriate relations between employees and residents.

The status of the investigation, its findings and whether it resulted in any disciplinary action was unclear Saturday. A spokesperson for the department did not respond to a phone message or email seeking an update on the investigation.

While at the York County Jail, Thayer implemented the Medication Assisted Treatment Program and expanded the jail’s programming and treatment services. In 2022, he was named the Maine Sheriff’s Association’s Manager of the Year. He is also a veteran who served in the U.S. Army during the Iraq War.