PORTLAND, Maine — Long Creek Youth Development Center Superintendent Jeff Merrill II has resigned, Department of Corrections Commissioner Joseph Fitzpatrick said Monday evening.

Merrill submitted his resignation from the youth prison citing “personal reasons,” over the weekend, Fitzpatrick said. Associate Commissioner Colin O’Neill will serve as the prison’s interim superintendent, he said.

The news comes less than a week after Merrill was placed on administrative leave. At the time, Fitzpatrick declined to say why Merrill was taken off the job, citing an “active investigation.”

“The investigation is stopped at this point,” Fitzpatrick said Monday. He declined to elaborate.

Merrill, who became superintendent in 2013 and has more than two decades of experience in corrections, could not be immediately reached for comment.

The youth prison has been embroiled in a series of controversies since last fall, when a 16-year-old transgender boy hanged himself while on suicide watch there.

After Charles Maisie Knowles’ death a young woman at Long Creek also tried to kill herself, and there has been a persistent pattern of self-harm among the severely mentally ill inmates that Long Creek is are not equipped to treat but is increasingly required to house, official reports obtains by the BDN revealed.

More recently, three 18-year-old inmates escaped from a Long Creek camping trip and stole an SUV before being arrested, according to police.

Following the death of her son, Michelle Knowles said that he was not getting appropriate mental health care because he was being detained at the prison awaiting trial rather than as a committed prisoner. Fitzpatrick denied this allegation at the time but also said later that there are young people in Long Creek who the prison is not equipped to treat.

The attorney general found nothing criminally suspicious in Knowles’ death and the department hired an outside expert to review its suicide prevention policy. That review was expected this month, although its findings have not been made public.

Joseph Jackson, who heads the Maine Prisoner Advocacy Coalition and regularly works with youth in Long Creek, said that there is more wrong at the prison than a change of leadership can address. He suggested that systemic problems in the criminal justice and mental health care systems are ultimately to blame, noting the disproportionate imprisonment of minority and mentally ill youth.

“Mental illness and suicide attempts have gone up and I don’t know that all of that lies on the shoulder of one person,” said Jackson. “There have got to be better options.”