SOUTH PORTLAND, Maine — The Maine attorney general’s office has found nothing suspicious in the death of a 16-year-old detainee who hanged himself late last year while confined at Long Creek Youth Development Center.

“Our review is complete. The death was the result of suicide and was not suspicious,” Attorney General Janet Mills said in a Jan. 31 memo to Maine Department of Corrections Commissioner Joseph Fitzpatrick.

Charles Maisie Knowles, a transgender boy, was found on Oct. 29, 2016, unconscious of hanging from the inside of the door of an isolation room at the youth center while on suicide watch. He died on Nov. 1 at Maine Medical Center.

Mills said her findings were based on investigations by the state medical examiner’s office, which determined that the cause of the teenager’s death was complications of hanging and the manner of death to be suicide, and the facility’s in-house criminal investigator, who found no evidence suggesting bullying or other mistreatment contributed in Knowles’ suicide.

Meanwhile, the state corrections department has hired an outside expert to review the youth prison’s suicide prevention policy.

The department decided that it needed a third party with no ties to the facility or Maine to examine what happened at Long Creek, according to the Jan. 21 document, which requested that the competitive bidding process be waived because of the “immediate need” to conduct the review.

To conduct this review, the department hired Lindsay Hayes of the National Center on Institutions and Alternatives, a Massachusetts group focused on criminal justice reform. Hayes has reviewed thousands of inmate suicides over his decades-long career and is charging the state $9,764.56, according to the waiver.

Knowles’ mother has claimed that her son’s suicide was preventable and that he was not receiving all the required mental health services because he was not a committed resident. The Department of Corrections has contested this claim.

Hayes said last month that his report would likely be completed within five weeks of his finishing the review at Long Creek on Friday. He did not know whether the findings would be made public.

BDN writer Jake Bleiberg contributed to this report.