The state paid a Standish man $500,000 to drop a lawsuit alleging he was mistreated in the 1990s by staff at the state’s juvenile correctional facility.

Matthew Keene filed suit in 2017 against 30 defendants, including the Department of Corrections and more than a dozen individuals, alleging that he was subjected to long, unwarranted periods of isolation and that restraints were used on him without proper cause, inflicting lasting mental damage.

The lawsuit was filed amid a rising call for dramatic reform or outright closure of the Long Creek Youth Development Center, where advocates say a disproportionate number of mentally ill children are held in a facility that is not designed to address their needs, and in some cases, their incarceration exacerbates mental health problems.

Long Creek also continues to be the focus of legal action on behalf of young people incarcerated there. Advocates for one 13-year-old boy in 2018 filed a federal lawsuit saying he was physically mistreated and injured by guards, who knocked out his two front teeth in a confrontation.

An attorney representing the same boy recently asked a Maine Supreme Judicial Court justice to order that he be released so he can get mental health care. Justice Ellen Gorman, who heard the petition, said the state still lacks appropriate mental health care for young people accused of crimes, but she denied the request that the court order the boy to be released.

Keene was held at the Maine Youth Center, now called Long Creek Youth Development Center, from 1995 to 1999, beginning when he was 13 years old.

The lawsuit alleges that Department of Corrections staff members routinely placed him in isolation for long periods, where he was held in a 6-by-8-foot cell for 23 to 24 hours per day, sometimes for up to 72 hours without access to exercise or educational opportunities.

Keene was also subject to the use of physical restraints in situations that did not meet the statutory limitations and requirements for their use.

Keene already had been diagnosed with “PTSD, depression, and anxiety, among other serious conditions,” and the excessive use of isolation and restraints exacerbated his condition, the lawsuit alleges.

The lawsuit alleges that the Maine Youth Center’s staff denied Keene the right to mental health treatment and consistently punished him instead of providing rehabilitative services, which exacerbated his mental illness.

“My client has been under a severe disability caused by the abuse that he suffered,” Keene’s attorney, Peter Clifford of Kennebunk, said in 2017, after the suit was first filed.

The settlement, dated April 22, ends Keene’s claims against the state. The federal case was dismissed on June 6. No one admitted fault in the case, and the state still denies liability while paying the settlement to avoid litigation, according to the settlement agreement, a copy of which was provided by the Office of the Attorney General in response to a public records request.

The settlement, while a public record, prevents either party from publicizing the terms of the agreement, and stipulates that in response to media inquires, the parties are permitted only to release a prescribed statement: “The matter has been resolved to the mutual satisfaction of all parties.”

Clifford did not return email and phone messages seeking comment.

A phone number for Matthew Keene could not be located, and the state Attorney General’s Office declined further comment.

The state has already convened a working group to study and make recommendations for the future of Long Creek, where Corrections Commissioner Randall Liberty has floated the possibility of converting the 165-bed facility into a women’s prison.

Advocates say that current best practice for treating and rehabilitating youthful offenders requires community-based options that do not include institutionalization. Currently, children from far-flung communities around Maine are transported to the locked South Portland facility, removing them from their communities, home and school life and native networks of support.

The facility, which has a capacity of roughly 165, was budgeted to spend $16.2 million in the latest fiscal year, and houses roughly 50 children, or roughly $320,000 per child per year. The state in the past has touted the small number of children housed there as a testament to a successful effort to divert many youths from the criminal justice system. In the early 1990s, roughly 300 children were incarcerated statewide.