Westport man sees his murder conviction overturned 30 years after death of girlfriend’s child

A Westport man has expressed his innocence for 30 years. Last week, he had his guilty verdict overturned.

According to the Commonwealth of Massachusetts, a jury in the Superior Court convicted Brian Peixoto of murder in the first degree of three-year-old Christopher Affonso Jr, his girlfriend’s son, and was sentenced to life without parole in MCI Concord.

The Commonwealth’s account states that on January 22, 1996, in Westport, Brian Peixoto was home with his girlfriend Ami Sneed and her young children, Christopher and Tarissa, whom he often cared for.

That morning, after Christopher wet the bed, Peixoto changed him. The boy appeared “wobbly” at breakfast, fell asleep in Peixoto’s truck, and was kept home from school. When Ami returned that afternoon, she noticed a new red bump on Christopher’s head. Peixoto said he had fallen down the stairs.

Later, while Ami was upstairs, a houseguest heard bumping and crying from the basement. Peixoto claimed Christopher had fallen down the stairs again. After the guest left, only Peixoto, Ami, and the two children remained. Following a heated argument in which Ami said she was moving out, she went upstairs to smoke a cigarette.

Ami then heard Tarissa calling her and four or five loud bangs from the basement. She found Peixoto on his hands and knees cleaning up vomit, with Christopher lying motionless on the floor beside him. Peixoto picked up the boy, whose eyes were rolling, and said, “Brian will never yell at you again. Come on, Buddy.”

They rushed Christopher to a fire station and then by ambulance to a Fall River hospital. En route, Peixoto claimed the boy had a seizure and warned Ami that if he survived, the hospital might not return him “because of the bruises.” At the hospital, he said Christopher had been banging his head on the floor before taking Tarissa and leaving.

It was ruled that Christopher died from blunt force trauma to the head. The medical examiner found multiple recent scrapes and contusions on his head, arms, back, legs, chest, and genitals.

Peixoto, his representation, and supporters, however, have a different account that they say can now be proved through evidence, which warrants a new trial.

According to a 2024 filing by Peixoto’s legal team, the Commonwealth’s medical examiner prematurely and erroneously concluded that Christopher’s death was due to a violent assault.

The filing also alleges that the child abuse expert in the case testified well beyond his area of expertise and falsely attributed findings to the medical examiner.

The reexamination of evidence shows that no one beat Christopher to death, according to the filing, and that the child was not a healthy, well-cared for child and that the bruises were from an earlier fall.

The paperwork also alleges that Christopher was stumbling, tripping, and acting drunk the morning of his death, yet Sneed failed to take the child to a medical appointment that morning.

The new evidence reportedly shows that Christopher had deadly sodium and chloride levels detected at the hospital the night he died. Lab results and records also established that Christopher had PTDI, Post-Traumatic Diabetes Insipidus, triggered by a traumatic impact to his skull which took days, not hours, to develop.

The post-conviction re-examination of the child abuse expert’s testimony also alleges that he gave misleading and false testimony.

The filing alleges that Christopher’s head injury that caused his death could not have happened that day due to the new revelations that it only became fatal because it went untreated for so long and that there was no reliable evidence that his bruises were caused that night either.

Lastly, the legal argument also suggests that the new evidence undermines Ami Sneed’s credibility, and that the evolution of her account was motivated by an awareness of her own neglect and desire for her to cover for herself.

On May 26th, 2026, Judge Daniel O’Shea issued his decision overturning Peixoto’s conviction.

“It is sufficient that there is a substantial risk of a miscarriage of justice from the jury’s failure to hear any evidence challenging the testimony of the Commonwealth’s trial experts that Christopher’s fatal brain injury was caused by extreme force intentionally inflicted on the date of his death.”

Judge O’Shea concluded, “Had the jury been presented with all the evidence proffered at the evidentiary hearing, they may have concluded that the Commonwealth failed to prove beyond a reasonable doubt that Peixoto inflicted head trauma on Christopher.”

 “Ultimately, however, fundamental fairness requires that a judgment of guilt or innocence be rendered by a jury informed about, not ignorant of, a scientifically plausible alternative explanation for Christopher’s tragic death. The testimony proffered at the evidentiary hearing would have bolstered Peixoto’s trial defense that someone else could have been responsible for causing Christopher’s fatal head injury or that said injury was accidental. The absence of such evidence created a substantial risk of a miscarriage of justice.”

Court records show that Peixoto is still being held without bail and has a conference to review status on June 4th.

An appeal of the ruling has been filed by the Commonwealth.