The only man on death row in New Hampshire spends his days alone in a concrete cell with a mattress, a sink, a toilet, and a tall, narrow window. His visitors are members of his legal team, who file the court documents that constitute his only communication with the wider world.

To the mother of the man he murdered, Michael Addison is a swaggering killer she forced herself to stare down in court. To the psychologist who interviewed him for his defense last year, he is a deeply traumatized and sometimes-suicidal person broken by a childhood filled with violence and abuse.


But as the state grapples with the likelihood that the Legislature will vote this month to override a gubernatorial veto and repeal the death penalty, Addison looms large on both sides of the debate. He is a black man in an almost all-white state who killed a police officer and father of two, and who was sentenced to death weeks after a white millionaire also facing the death penalty was given life in prison. In the philosophical clash over ethics and justice, Addison is a brutal fact.

New Hampshire State Prison for Men, where Michael Addison is housed in the Secure Housing Unit. New Hampshire Department of Corrections

“When we talk about the death penalty in the abstract, there’s a growing movement toward abolition because of concerns about fairness, accuracy, discrimination, and cruelty,” Northeastern University law professor Daniel Medwed said. “But on a granular level, in an individual case, it gets complicated.”

***

Manchester police Officer Michael Briggs was an hour from the end of his shift in the early morning of Oct. 16, 2006, patrolling the east side of the city on his bike, when the call came in: a gunshot fired during a domestic incident in an apartment. He and his partner pedaled to the scene.

Briggs knew Addison. Several years earlier, he had been the officer on scene when Addison was shot, and he had tended his wound. He was aware now that Addison was coming off a crime spree with a friend and that both were wanted in a shooting. But Briggs could not have known of the threat Addison made when friends told him the police were searching for him: He had vowed to shoot.


Manchester police Officer Michael Briggs. Manchester Police/File 2006

Briggs and his partner searched the apartment building with other officers, but Addison and his friend were gone. The two officers set off into the darkness.

Briggs was 35, quiet and direct and funny, a former Marine who grew up prowling the woods and swimming holes of Epsom, N.H. He and his father were always outdoors, talking on walkie talkies, digging for worms to use as fishing bait, and trapping and hunting deer and birds, said his mother, Maryann Briggs. Michael wanted to be just like his dad, and he followed him into police work.

In the Manchester department, he was known for his love of his wife and two sons, his bravery, and the good-natured, respectful way he interacted with everybody, criminal or civilian. Before joining the force, Briggs had worked as a corrections officer in the county jail, and he often ran into former inmates out on the street, Manchester officers who knew him well say. At night, officers would converge on the local bars as they started to let out for the night, and it was not unusual to hear a happy, drunken voice call out, “C.O. Briggs!”


Briggs always did the right thing, fellow officers thought. He had his head on straight. He could defuse any situation. He never seemed afraid.

On the night he was killed, Briggs and his partner spotted Addison and his friend just before 3 a.m., walking down an alley with their hoods pulled up.

“Stop, police!” Briggs shouted. Addison’s friend halted, but Addison kept walking, his hands near the gun tucked out of view in his waistband. Briggs shouted again, and Addison hunched his back and slowed. Briggs was an arm’s length away when he shouted for a third time.

Now, Addison spun. In a sweeping motion, he raised the gun and fired a single shot straight into Briggs’s head.

Briggs fell. Addison ran.

Police found Addison after a massive search, hiding in his grandmother’s apartment in Boston.

Briggs never regained consciousness. He died the next day.

***

Michael Briggs’s funeral procession wound for miles through downtown Manchester, N.H. Jim Cole/Associated Press/File 2006/Associated Press

The outcry over Briggs’s death swept New Hampshire. His funeral procession wound for miles through downtown Manchester, thousands of police officers escorting a hearse and a riderless horse into a baseball stadium filled with hundreds of civilians, where, according to local media, his casket was laid on home plate.

His killing sparked heated debate over capital punishment. Then-Attorney General Kelly Ayotte announced she’d seek the death penalty, and legislators earmarked a budget for the case bigger than her office’s entire litigation budget for that fiscal year, legislators said at the time. Then-Governor John Lynch called the killing of Briggs a crime that “strikes at the very heart and fabric of our society.”


The state hadn’t executed anyone since 1939. Two men were sentenced to death in 1959, but their lives were spared when the US Supreme Court struck down state death penalty laws in 1972. The last time the death penalty was sought before Addison was in a 1997 killing of an Epsom police officer, but that case ended in a plea arrangement that allowed the defendant to avoid execution. Execution was rarely pursued and hotly contested when it was.

But then, a little more than a month after Addison killed Briggs, police arrested New Hampshire self-made millionaire John “Jay” Brooks and charged him with murdering a handyman in an elaborate scheme involving three hired men. Murder for hire is a capital offense in New Hampshire. Suddenly, the state was seeking the death penalty against two defendants in separate cases at the same time — one black, one white.

New Hampshire self-made millionaire John “Jay” Brooks was charged in 2006 with murdering a handyman in an elaborate scheme involving three hired men. Bob LaPree/Union Leader via Associated Press/File 2007/UNION LEADER via AP

Brooks, who made his fortune inventing a plastic instrument tray for surgeries before selling his company and moving to Las Vegas, had plotted for two years to kill Jack Reid Sr., whom he had hired to help him move some of his belongings.

Reid, 57, was an Army veteran and retired trucker with five children; he lived quietly in a trailer parked behind an auto repair shop in Derry running a business called “Man with a Dump Truck.” His daughter remembered that once he had talked excitedly of doing a job for a millionaire inventor, saying the man was important — and a friend. He had never mentioned any trouble.


But Brooks, according to court documents and prosecutors at the time, harbored a simmering obsession, believing that Reid had stolen motorcycles, jewelry, and an urn containing his father’s ashes from Brooks’s rental truck and trailer in September 2003, when he had worked for him.

In late 2003, he paid two men $5,000 to kill Reid, but the attempt failed. Then, in June of 2005, he succeeded. He hired his accomplices, flew to New Hampshire, and lured Reid to a friend’s home. Brooks and his accomplices beat Reid to death, wrapped him in a tarp, and left his body in his truck in a Target parking lot in Saugus.

Brooks and Addison were different in many ways beyond race. Brooks, 54, had long been seen as an upstanding member of society, had served in the military, and had invented a medical device that helped surgeons care for patients. Addison was the child of a teenage drug user who, he said, once tried to sell him to a drug dealer for crack, according to court documents. He grew up amid gang members who solved problems by shooting each other, and he was in and out of jail for acts of violence from the time he was a teenager. Both of their victims were white, but the man Brooks killed lived a simple, anonymous life; the man Addison killed was publicly beloved and mourned.

Both were found guilty by New Hampshire juries. Brooks was found to have planned his crime meticulously. Addison was found to have acted impulsively.

Only Addison received the death penalty.

“It’s harder to kill somebody who looks like you than it is to kill somebody who doesn’t look like you,” said attorney Albert “Buzz” Scherr, a professor of law at the University of New Hampshire School of Law who spent 13 years as a public defender and has tried homicide cases and one capital case. “Michael Addison fits the stereotypical, superficial profile of ‘the other.’ And John Brooks doesn’t.”

***

For decades, one of the clearest voices in New Hampshire arguing against the death penalty has been Representative Robert Renny Cushing, a Hampton Democrat. Jim Cole/Associated Press/File 2014/Associated Press

For decades, one of the clearest voices in New Hampshire arguing against the death penalty has been Representative Robert Renny Cushing, a Hampton Democrat whose own father was murdered and who is the primary sponsor of the repeal effort that is currently awaiting a final vote, House Bill 455.

“I think the death penalty is a human rights violation,” Cushing said. “I think it’s a failed public policy. I think it doesn’t work for law enforcement. It certainly doesn’t work for victims of crime.”

Cushing’s father was shot to death in 1988 by a neighbor in the doorway of his family home. Cushing had always been against the death penalty, he said, but he had never had to examine his beliefs. But when a friend told him he hoped the shooter would get the death penalty, Cushing recoiled. Giving in to a desire for vengeance, he said, would mean he had lost his father and his values. The man who killed his father was an off-duty police officer who tried to claim insanity as a defense; he was ultimately sentenced to life in prison.

New Hampshire’s death penalty statute can only be applied to certain types of murders, including the murder of an on-duty police officer or judge, murder for hire, murder connected to a kidnapping, and murder during a rape. Bills aiming to abolish capital punishment have come before the Legislature nearly every session for the past two decades, Cushing said, and at times, repeal advocates have come close to success. In 2000, the House and Senate both passed legislation to end the death penalty, only to see it vetoed by then-Governor Jeanne Shaheen. In 2014, repeal legislation failed on a tie vote in the state Senate. Last year, current Governor Chris Sununu vetoed a bill identical to House Bill 455.

When Governor Chris Sununu vetoed the repeal bill this month, he did so from inside the Manchester Police Athletic League Officer Michael Briggs Community Center, blocks from where Officer Michael Briggs was killed, flanked by police officers and Briggs’s family. Nick Stoico/The Concord Monitor via Associated Press/The Concord Monitor via AP

Today, though, the death penalty seems poised to fall. The House and Senate both passed the current bill, and while Sununu vetoed it May 3, the Legislature appears for the first time to have enough votes to override the veto. The House is expected to vote on it Thursday. If that override passes, the Senate is expected to vote the following week.

The repeal would not be retroactive, and so it would not directly affect Addison’s case, though legal experts and precedent suggest the courts would not allow him to be executed if New Hampshire no longer had the death penalty.

Still, Addison has figured prominently in the public dialogue. When Sununu vetoed the repeal bill, he did so from inside the Manchester Police Athletic League Officer Michael Briggs Community Center, blocks from where Briggs was killed, flanked by police officers and Briggs’s family.

“This is common sense,” Sununu said. “New Hampshire has always exercised great prudence, great responsibility, in its application of the death penalty. I firmly see, along with many folks across this state, this bill is an injustice. Not just to Officer Briggs and his family, but to law enforcement and other victims of violent crime across the state.”

Those who believe in the death penalty say it protects police who put their lives on the line to protect the people, and they say it serves as a deterrent to criminals contemplating heinous acts. Some crimes, they say, deserve the ultimate punishment. And if anyone deserves death, they would say, it is Michael Addison, an irredeemably violent criminal who killed a cop, a hero, a husband, a father.

Cushing and other repeal advocates cite the enormous financial cost of capital punishment, with millions of dollars poured into endless appeals that can turn killers into celebrities. They talk about the impossibility of removing human error from the judicial process, and they point to the exonerations of death row inmates proven innocent by advances in DNA analysis and other scientific testing.

They also raise the stark racial inequities in how the death penalty is applied. More than a third of defendants executed in America since 1976, when the Supreme Court reinstated the death penalty, have been black, according to the Death Penalty Information Center, even though only 13 percent of the American population is black. And a person who kills a white victim is disproportionately likely to be put to death — more than three-quarters of victims in cases resulting in execution were white, according to the information center, even though only half of murder victims nationally are white. New Hampshire is 94 percent white.

In this context, some repeal advocates say, the Addison case stands out as a case study on the flaws in the system.

“It became somewhat freakish to think that of the thousands of homicides that have taken place since 1939, we singled out one to impose the death penalty,” Cushing said. “And the only person we decide to put on death row is African-American.”

***

To many of those who live every day with the tragedy of Briggs’s death, Addison’s sentence is the only just outcome, and the thought that it could be stripped away is a betrayal.

“These parents lost their only son,” Manchester police Captain Allen Aldenberg said. “They’re looking for what’s right.”

Maryann Briggs sat through every single court hearing in Addison’s trial and subsequent appeals, she said. She listened to the terrible, clinical details of his autopsy, the savagery inflicted on her boy. When the prosecutor brought out the clothing her son was wearing the night he was killed — his shirt, his belt, his boots, his socks — she forced herself to look.

“Mike was a good boy,” she said. “He’s not here anymore. He’s not driving in the driveway. He’s not here for our Sunday dinners. He’s just not here anymore.”

The Manchester officers who loved Briggs got his badge number tattooed on their bodies. They carry guilt — could they, somehow, have prevented his murder? The anniversaries tick by, and suddenly, a sergeant who looked up to Briggs like an older brother is 35 with a wife and kids, like Briggs was when he was killed, and his understanding deepens, and the pain is new again.

The Legislature will decide the law, and the courts will probably decide Addison’s fate. The death penalty is about more than one case, said Pat Sullivan, executive director of the New Hampshire Association of Chiefs of Police.

“However, Michael Addison is in our memories,” Sullivan said. “Michael Briggs is in our memories.”

Jeremiah Manion, Victoria McGrane, and Jonathan Saltzman of the Globe Staff and Globe correspondent Sarah Schweitzer contributed to this story. Evan Allen can be reached at evan.allen@globe.com. Follow her on Twitter @evanmallen.