On a snowy March morning in 2017, half a dozen men walked out of the state’s maximum security prison, their sentences at an end. Some beamed as they rushed into the arms of tearful relatives. Others were grim-faced and tense, apprehensive about their new freedom.

Lisa Newman-Polk looked on anxiously as she waited for Shaquille Brown’s turn to come. She had been Brown’s lawyer during much of his three years in prison for violating probation in an assault case, and was the only person to visit him in all that time. No relatives, not even his mother, had come.

As she watched the reunions, she wondered how he would feel when he stepped through the door. Brown had spent almost his entire adolescence incarcerated, much of it in solitary confinement. He had told her many times he was terrified of the world outside.

At 22, he was leaving Souza-Baranowski Correctional Center with no job prospects and no money. He wanted a better life, but couldn’t imagine how it would happen. He couldn’t see even the faintest outline of a future.

“I was sitting in my cell thinking one night: ‘I’m not going to be nothing in life but a dog locked in a cage,’ ’’ Brown wrote Newman-Polk shortly before his release. “When is all of this going to end? I been in hell all my life.’’

Finally, Brown walked hesitantly into the lobby, wearing the rough denim shirt and pants given to departing inmates. He saw Newman-Polk and his girlfriend, Tanashe King, and smiled widely, then rushed to them and hugged them close.

King, a slight, slender woman Brown had known since he was 9, pulled out a bag of new clothes and asked him if he wanted to change. He shook his head.

“I just want to go,’’ he said softly. He put on a black windbreaker King had brought him, and walked out of the prison, carrying only the 30-day supply of antipsychotics prescribed to moderate his severe mood swings and impulsive behavior.

Just before he was released, some correction officers at Souza-Baranowski told him that he would be back behind bars soon enough. They were right.

Within three months, he would be charged with murder.

Advocates say the dearth of services for returning convicts consigns many much like him to failure, undercutting the state’s longstanding efforts to reduce stubbornly high recidivism levels. This past fiscal year, the state allocated just $90,000 to a community-based reentry program, funding a single halfway house in Worcester.

Meanwhile, even as the incarceration rate in Massachusetts has fallen, reoffending levels remain high, a cycle that costs the state millions and puts public safety at risk.

More than half of the men who left the state’s maximum security prisons in 2014 were reincarcerated within three years, according to the state Department of Correction’s latest figures.

Many released convicts, like Brown, have chronic mental health conditions that clinicians say have been exacerbated by years in prison and time spent in solitary confinement, which prison officials call segregation. In many cases, they leave prison more troubled and unstable than when they arrived, specialists say, ill-equipped to handle the demands of life outside.

Carol Mici, deputy commissioner of clinical services and reentry at the corrections department, said officials generally try to move prisoners near the end of their sentences to lower-security facilities to help ease their transition into the community. But inmates who have tried to escape or have been deemed violent may not qualify for such transfers, and the number of reentry programs — community-based initiatives that help released offenders find housing, work, counseling, and substance use disorder treatment — has sharply declined in recent years.

Even as lawmakers have enacted a broad overhaul of the state’s criminal justice system, five reentry programs have closed, largely because of gradual cuts in support from the state and federal government.

“There is very little help for people when they come out,’’ said Bruce Western, a Columbia University sociology professor who has published a book about 122 men and women he followed in 2015 during their first year out of Massachusetts prisons. “The trauma and human frailty in the population that we’re talking about is so acute, and there is a massive need for assistance there that goes unaddressed.’’

Newman-Polk became Brown’s lawyer in 2015, when he was accused of assaulting correction officers. Brown would eventually be acquitted, but the charge led to a prolonged stint in isolation. A clinician by training, she grew close to Brown, who confided to her about his difficult childhood and the anguish of his years in custody.

“I just felt like Shaquille was someone who needed a lot of support, who had been thrown away by society,’’ she recalled. “Frankly, that hurt me.’’

As his release date neared, Brown decided he didn’t want to go back to Dorchester, where he had grown up and made some dangerous enemies. Newman-Polk found a halfway house in Worcester, far enough away that he would feel safe. But prison officials told her not to bother applying — the Worcester facility never accepted inmates from Souza-Baranowski.

A prison reentry officer had spent months searching for transitional programs, and thought he had finally found one that would help Brown find work and get his GED. But after accepting him, the program reversed course, saying he posed too high a risk.

Mici said that type of dispiriting response is not uncommon, even from programs set up to help those most likely to reoffend.

“Everyone says they’re welcoming to these inmates coming home,’’ she said. “They’re not.’’

In July of this year, two years after a state-appointed commission highlighted Massachusetts’ high recidivism rate, Governor Charlie Baker and the Legislature approved a budget that includes $5 million for grants to community-based programs for returning inmates, a major increase but still far less than what other states spend. Last year, Ohio spent more than $66 million for state-contracted halfway houses while New Jersey earmarked $65 million, according to Community Resources for Justice, a Boston-based organization that provides services to returning inmates.

According to recent state prison figures, those states have much larger correctional populations — just under 50,000 in Ohio and 19,400 in New Jersey compared with about 8,000 in Massachusetts. But New Jersey and Ohio are still spending significantly more per prisoner on reentry programs. Even with the boost in funding, Massachusetts will spend roughly $625 per inmate for such programs in the upcoming fiscal year, compared with $1,300 spent by Ohio and $3,300 spent by New Jersey.

Proponents of increased funding say transitional programs pay for themselves many times over.

“They’re all coming back and they’re all going to be living in our community,’’ said John Larivee, president of Community Resources for Justice. “It’s a challenging world for them that they don’t know how to navigate.’’

No reliable male role models

The Globe decided to follow Brown after his release from prison as a way to examine the challenges offenders with mental health problems can face when they leave prison.

The newspaper first wrote about Brown in 2007; he and his little brother, Brajon, had started their own gang called “Bangin’ Little Thugs.’’ Brown was just 12.

Brown’s mother drank and smoked crack while she was pregnant with him, leaving him with a serious neurodevelopmental disorder that made it hard to control his impulses and read social cues. Brown was never close to his father, who would die, when Brown was still a young boy, from dementia.

It fell to Brown’s grandmother to raise him and three of his siblings. He rarely got in trouble in school, his older brother said.

But when his grandmother died, the loss set him adrift. He went back to live with his mother, who continued to struggle with addiction. Brown began to drink and smoke pot, and stopped taking the Adderall doctors had prescribed for his attention deficit disorder because it made him sluggish.

He had no reliable male role models; indeed, no real role models at all. His older brother, a gang member Brown worshiped, moved to Georgia in his early 20s and was soon was arrested for aggravated assault, a charge that led to a 10-year sentence. Back home, Brown’s uncle beat him regularly with a belt. Brown became quick to fight, wary of the world, convinced he always had to strike first.

“He always had that territorial ‘I have to protect myself or somebody is coming for me,’ ’’ said Tanashe King, Brown’s childhood friend.

King said he was never rough with her. They were boyfriend and girlfriend by the time he was in sixth grade, skating loops together around the Chez-Vous Roller Rink in Mattapan.

“We were soul mates,’’ King said.

As Brown grew older, his anxiety got worse, and his anger caused him to lash out. He was arrested repeatedly for incidents that ranged from larceny to assaulting a police officer. In 2008, at 13, he was committed to juvenile detention.

In 2011, he and another teenager beat a staff member who refused to let them hang out in the rec room of a youth detention center in Roslindale. After the man fell to the ground, Brown kicked him in the head, according to police reports.

He was sentenced to 2½ years in custody and five years of probation. Eventually, he was transferred to county jail.

At 19, he was released on probation but was arrested less than four months later, in May 2014, on charges of illegal gun possession. The charge was ultimately dismissed, but the arrest was enough to send him to MCI-Concord for the next three years.

In county jail, Brown had been prescribed antipsychotics to help him cope with the emotional and mental problems that specialists said made it hard for him to control his impulses.

But in state prison, officials took a strikingly different course, determining that Brown did not need regular mental health treatment, according to a May 2016 report by John Beland, a clinical social worker who evaluated Brown at the request of his lawyer, Newman-Polk. She was trying to have him transferred to a less restrictive unit.

Brown had been sent to a segregation unit after prison officials found marijuana in his cell. In June 2015, he was moved from MCI-Concord to MCI-Shirley, where he was accused of biting one of five correctional officers who stormed into his room after Brown placed his bed mattress over his cell window, according to an incident report.

Brown, who denied biting the officer, said he had covered his window in protest. Officers had refused to let him shower and wash off chemical spray that had been used to subdue him in another incident earlier that day, Newman-Polk said.

Newman-Polk, then a public defender, was assigned to his criminal case. Brown was acquitted of the assault charges, but that did not change his punishment in prison: two years in the Departmental Disciplinary Unit, where inmates are in isolation 23 hours a day.

At times, Brown felt so alone that he deliberately antagonized officers so they would come to his cell and yell at him. Any human contact was comforting.

“The DDU was rough,’’ Brown later told a prison psychiatrist. “I was always acting up, getting in trouble, just to get out of the cell.’’

He wound up spending 10 months in solitary confinement, which Beland, the social worker, described as an “act of gross negligence’’ that worsened Brown’s psychological condition.

Prison officials declined to discuss Brown’s case, citing rules that protect prisoners’ privacy. Mici, the DOC official, said segregation is reserved for “egregious offenses’’ when inmates become a danger to themselves or others.

In March 2016, the department transferred Brown to a secure treatment program at Souza-Baranowski for inmates with behavioral and mental health problems who have been sentenced to the DDU but are deemed too ill for such isolation.

“The mental health team finally figured out that he had a neurodevelopmental disorder and determined that he was functionally impaired,’’ Newman-Polk said. But Newman-Polk said conditions in the secure treatment program, where inmates are confined to individual cages for group therapy and are placed in isolation — known as “accountability cells’’ — as discipline, were hardly better than the DDU.

Inmates, including Brown, also complained to Prisoners’ Legal Services, an advocacy group, that officers were baiting them into fights or hurting themselves, according to a letter the group sent to prison superintendent Steven Silva in June 2016.

In one incident, Brown was in the isolation cell when the door suddenly opened. Surprised, Brown stepped out and was immediately grabbed by officers who pulled him to the ground, twisting his ankle. One officer punched him in the head, according to the letter. Jason Dobson, a spokesman for the Department of Correction, said he could not respond specifically to the allegations because of state laws governing the confidentiality of an inmate’s prison record.

“What we can say is that all allegations of officer misconduct are thoroughly investigated,’’ Dobson said.

Beland, who for 11 years worked in the state prisons as a clinician and a supervisor of various mental health teams, recommended that Brown spend his last year of his sentence in the prison’s residential treatment unit, where inmates receive psychotherapy, take life skills classes, and spend more time outside.

“With the implementation of these supportive psychotherapeutic measures, it is my clinical opinion that the likelihood of Mr. Brown functioning in a safe and productive manner within the community upon release would increase dramatically,’’ Beland wrote.

Newman-Polk sent the report to a deputy commissioner, hoping it would lead to a transfer. The request was denied.

‘I don’t feel safe in Boston’

After his release, Brown had nowhere else to go but Boston.

He moved in with King and her 5-year-old son in her Dorchester apartment on Harvard Avenue, close to where he grew up and far too close to potential rivals who might want him dead.

Despite his terror, he tried to start a normal life with King.

His first weekend back, he and King celebrated her son’s birthday at Chez-Vous, the roller rink they went to as kids. King, a hospital chef who worked double shifts to support her son, rented out the rink and spent $200 on pizza, chicken wings, and french fries.

Brown was not the boy’s father, but he was tender and patient with him, and babysat while King was at work. But he struggled to find any other purpose.

He spent hours cleaning the apartment and he worked out obsessively, doing pullups, push-ups, and sit-ups in the backyard. He rarely wanted to go out, even for a walk around the block.

“I don’t feel safe in Boston,’’ he would say.

He hadn’t received psychiatric treatment since leaving prison. His reentry coordinator had lined up an appointment with a primary care doctor, who could refer him to a counselor. But Brown didn’t show.

Prison officials had asked the Department of Mental Health to take him as a client so he could have streamlined access to psychiatric services. But Newman-Polk said they denied his petition, saying his condition was not serious enough.

In the past decade, DMH has received roughly 50 applications annually from prisons and jails. Only 27 percent met its criteria that a patient demonstrate long-term functional impairment, according to the agency.

“Under state law, [DMH] must prioritize its services to individuals with long-term, severe, and persistent mental illness,’’ said Daniela Trammell, a spokeswoman for the agency.

Brown was dejected but not surprised when he learned that yet another agency had rejected him. In a letter to Newman-Polk, Brown said he was increasingly worried he wouldn’t last long on the outside.

“I feel like this place is setting me up,’’ Brown wrote. “To just come home to get killed or come back.’’

Three weeks after his release, Newman-Polk took Brown to lunch at a vegetarian restaurant in Cambridge. A strict vegan, Newman-Polk was hoping to make Brown a convert. As she drove him from Dorchester, she tried to make a connection between livestock waiting to be killed and men locked up in prison.

“You don’t think anyone should be held in cages?’’ Newman-Polk asked him.

“Nah,’’ he replied as he stared out at the Charles River.

Then, he rapped some lyrics that he had begun writing when he was 13.

My moms don’t love me/My pops don’t like me.

My uncle was a crackhead, he always trying to fight me.

Chilling in the hood the cops always try cuffing me, cuffing me, cuffing me.

Newman-Polk had thought Brown would feel safer in Cambridge. But Brown was jumpy. At the restaurant, he sat against the wall, so he could see everyone who came in.

“I don’t like a lot of people seeing me,’’ he said.

As they ate, Brown admitted he wasn’t doing well. He was having trouble sleeping, and sometimes paced the halls in the middle of the night. King had begun sneaking NyQuil into his drinks, hoping it would help him rest.

He had gone to the Natick Mall and TGI Fridays in Dedham to get out of Boston, he told Newman-Polk. But he couldn’t relax. He would hop out of the car and bolt inside, terrified. “Something is wrong with me,’’ he told Newman-Polk.

In May, King took Brown to Nantasket Beach with her son and his two young nephews. King laid out a blanket, but Brown could hardly stay still. When people passed, he asked King why they were looking at them.

It wasn’t long before King decided she couldn’t take the stress of the relationship anymore. She told Brown they had to break up. They could still be friends, she told him.

“He wasn’t having none of that,’’ King said.

For the first time, Brown hit her, she said.

He punched her in the face and back, then put his hands around her neck and squeezed, according to a police report. He allegedly smashed a wooden chair, picked up a broken shard, and held it to her throat. He fled before police arrived.

Through a lawyer, Brown denied the charges, which were ultimately dismissed.

King didn’t hear from him for weeks. But in July, he called. He had been arrested for the assault and pleaded with her to come down to the station.

“What can I do for you?’’ she asked him. “I can’t do nothing.’’

Brown probably did not know it at the time, but police were also investigating him for murder.

‘He needs to be in a hospital’

When Brown was a boy, he was drawn to the church across the street from his grandmother’s house. On Sunday mornings, he would sneak out of his house on Washington Street and sit by himself in the back of the sanctuary, listening to the choir and the preacher. It was peaceful there.

There had been so little peace in his life. And after leaving prison, there was none. He was terrified, his brother said. It felt inevitable that someone would come after him.

It’s unclear what happened to Brown between May, when King left him, and his arrest in July 2017. But police say he connected at some point with a man named Keith Cousins who had a history of firearms charges and had been incarcerated at Souza-Baranowski around the same time as Brown.

Suffolk County prosecutors have not been able to establish that the men met in prison, but say that Brown and Cousins were together the morning of June 28, driving in a royal blue Honda Accord coupe. Prosecutors say they were looking for Christopher Austin, a 20-year-old baggage handler at Logan Airport who walked from his Dorchester home to Ashmont Station each day to get to work.

When Austin left a convenience store near the station with some snacks, a man in khaki pants approached him. They spoke briefly, then a man police identified as Brown suddenly pulled out a gun, shooting Austin once in the head, authorities said. He died two days later.

Prosecutors say Austin was a hard worker with no criminal background, and have offered no explanation for his murder. A law enforcement official who spoke on condition of anonymity said investigators believe Austin may have been mistaken for a rival of the killer.

Austin’s mother, Grace Richardson, said her son was a homebody who loved to hunker down in the makeshift recording studio he fashioned in his bedroom closet and compose music on his computer.

“He always loved music,’’ Richardson said. “His first toy was headphones.’’

At the arraignment, Brown and Cousins pleaded not guilty to first-degree murder charges. Brown’s mother sat in the gallery, weeping. Austin’s family sat across the courtroom, wearing buttons with his photo. Brown’s trial is scheduled for March.

Tanashe King has talked to him by phone, but has not visited him in the Suffolk County jail where he is being held without bail. She doesn’t want to be with him anymore, but she wants him to know she still loves him.

She said as much when a prosecutor asked, after Brown was charged with assaulting her but before the murder charge, what should happen to him.

Something other than jail, she said.

Life had damaged him and he had made terrible choices. But jail had broken him. She had seen that firsthand.

“He needs to be in a hospital. He needs to be on his medication. He needs to be stable,’’ King said. “He needs to know that he doesn’t have to keep fighting. Nobody is fighting him.’’

Maria Cramer can be reached at mcramer@globe.com. Follow her on Twitter @globemcramer.