The number of inmate suicides in Massachusetts’ county jails dropped to three last year — the lowest tally since 2011 and a sharp decrease from 10 suicides the year before in jails run by county sheriffs, according to data compiled by the New England Center for Investigative Reporting.

One factor could be fewer county inmates: Population in the state's 13 county jails fell by more than 9 percent last year to about 9,500 sentenced prisoners and men and women awaiting trial.

County sheriffs have faced lawsuits in recent years over their treatment of mentally ill inmates and came under fire for a rising number of suicides. A May 2017 story by the New England Center for Investigative Reporting found at least 42 men and women had died by suicide in the state’s county jails over a 5-year period. The state does not track prisoner deaths in county jails.

Middlesex County Sheriff Peter Koutoujian, who is also president of the Massachusetts Sheriffs Association, said jails have stepped up efforts to prevent suicides.

“The fact that the numbers have gone down shows that we have been focusing on this. We have implemented new strategies and new ways to address this issue,” he said. “It’s [about] identifying people that are in crisis before they get to the point where they consider self-harm.”

In state prisons, which hold about the same number inmates, four prisoners committed suicide last year, the same as 2017.

Last year’s package of sweeping criminal justice reform legislation didn’t directly address suicide prevention, but the new laws are pushing both state prisons and county jails to broaden definitions of mental illness and to cut back on practices such as solitary confinement, a known factor in inmate suicides.

One reform will require both state and counties to reduce the amount of time mentally ill inmates can be held in solitary confinement to 72 hours.

Bonnie Tenneriello, a staff attorney at Prisoners’ Legal Services in Boston, said the new laws should also create more uniform mental health practices in the county jails, which have been largely unregulated by the state even though it spends more than $600 million a year to fund sheriffs’ departments.

Tenneriello is glad to see the lower jail suicide numbers but said jails and prisons still need to focus on treatment, not segregating inmates and exacerbating their mental problems.

“Even the people we think pose the greatest threat to our prisons, let's get them out of their cell, let's get them treatment,” she said. “Let's treat them like human beings, because locking them in a box is manufacturing suicides.”

Concern about the mental damage caused by confining prisoners to a cell for more than 22 hours a day dominated a recent public hearing in Boston — where former inmates, along with advocates, criticized top officials from the Department of Corrections and called for the agency to abolish the practice.

“When they put you in that cell, that room, you’re going to mentally die and spiritually die,” said Nicholas Gomes, a former state prison inmate who spent time in solitary. “This system, you’re creating monsters.

Critics said the state corrections agency is dodging the new law — which defines restrictive housing as confining an inmate to a cell for more than 22 hours a day — by drafting policies for units that hold prisoners in a cell for 21 hours a day. The agency didn’t respond to these charges and said it is working to implement the criminal justice reforms passed last year.

Bristol County's jails in North Dartmouth and New Bedford saw no inmate suicides last year, but over the past dozen years, 16 inmates have killed themselves in the Bristol jails.

Facing lawsuits and a call from the state attorney general last year for a state investigation of Bristol County’s treatment of mentally ill inmates, Sheriff Thomas Hodgson said his department hired a new clinician last summer who focuses on working with mentally ill inmates after they are released from a suicide watch cell.

“They can build a relationship with them to make sure that they're leveling out or in a good place mentally,” Hodgson said. “We try to follow very strict protocols around their recommendations.”

But Hodgson also does not expect the cycle of suicides to stop as a result, saying that an inmate’s suicidal urges are often beyond his staff’s control.

In Barnstable County, Sheriff James Cummings said his jail has not made any substantial policy changes to prevent inmate suicides. Cummings said the jail sees about 12 suicide attempts a year. In response to public records requests for inmate suicide information, his department did not initially disclose that Sean Williams Wallace, a 34-year-old pretrial inmate, attempted suicide in custody last July and died in September after he was released.

The state medical examiner ruled Wallace’s death a suicide from blunt force head trauma, but his death was not investigated by state police, which typically investigates jail and prison deaths. Barnstable jail officials would not release information about the circumstances surrounding Wallace’s self-injury inside its jail.

Chris Burrell is a reporter for the New England Center for Investigative Reporting, a nonprofit news center based out of Boston University and WGBH News. Hannah Schoenbaum is an intern at the New England Center for Investigative Reporting. For more, go to