The New Hampshire Supreme Court has thrown out Adam Montgomery's second-degree murder conviction in the death of his five-year-old daughter, Harmony Montgomery, ruling that trying the murder charge alongside a separate assault charge in a single trial violated his right to a fair proceeding. The state plans to try him again.
Montgomery remains behind bars. His convictions on abuse of a corpse, tampering with evidence, and assault still stand, and his combined sentence of 43.5 years on those charges and previously upheld firearms offenses is unaffected. But the murder conviction, the centerpiece of a case that drew national attention after a little girl vanished for years without anyone noticing, must now be relitigated from scratch.
The decision forces prosecutors back into a courtroom to prove, a second time, that Adam Montgomery killed the child whose body has never been found.
The high court's opinion zeroed in on a specific trial error: the decision to try the second-degree assault charge and the second-degree murder charge together. The assault charge stemmed from an incident in July 2019. The murder charge arose from a separate alleged attack on December 7, 2019, when prosecutors said Montgomery beat Harmony over the head after she soiled herself in her sleep.
Three witnesses testified they saw Harmony with a black eye in July 2019. Four witnesses, including two who observed the black eye, told jurors that Montgomery admitted striking the child. The court called the state's assault case "strong."
That strength became the problem. As Fox News Digital reported, the court concluded there was "a significant risk that the jury would draw the impermissible inference that because the defendant assaulted the victim before by striking her in the head, he must be the one who fatally assaulted her in December by again striking her in the head."
In other words, the July assault evidence was so convincing that it likely bled into the jury's consideration of the December murder charge, a charge that rested on far thinner ground. Only one witness linked Montgomery to the December assault believed to have killed Harmony.
The court's language was direct: "Trying the second degree assault and second degree murder charges in a single trial jeopardized the defendant's right to a fair trial."
The trial at Hillsborough County Superior Court in Manchester, New Hampshire, leaned heavily on testimony from Kayla Montgomery, Adam Montgomery's estranged wife and Harmony's stepmother. Kayla Montgomery testified against her husband after receiving a deal from prosecutors in exchange for her cooperation.
The defense challenged her credibility and attempted to shift blame for Harmony's death onto her. The high court noted that no evidence was presented to the jury showing Kayla Montgomery had ever physically assaulted the child, while multiple witnesses testified that Adam Montgomery had.
That factual contrast apparently did not save the conviction. The court found the structural problem, bundling two charges that shared similar alleged conduct but vastly different evidentiary strength, was enough to require a new trial on the murder count alone.
The New Hampshire Attorney General's Office wasted no time signaling its intentions. Michael Garrity, spokesperson for Attorney General John Formella, confirmed the office plans to retry Montgomery on the murder charge.
"We are disappointed by the Court's decision to order a new trial on the second-degree murder charge and we plan to pursue a re-trial on that charge."
Garrity emphasized that the ruling does not undo the rest of the case against Montgomery.
"Adam Montgomery remains convicted of multiple serious felonies arising from Harmony's death, as well as separate firearms offenses that were previously upheld on appeal. Montgomery's total sentence of 43.5 years for these additional charges stands and is not affected by the Court's decision today."
He added that prosecutors remain "confident in the facts of this case, the evidence presented, and the exceptional work of our prosecutors, investigators, and law enforcement partners." The murder case has been remanded to a lower court.
Harmony Montgomery's case exposed a series of institutional failures long before it reached any courtroom. Investigators in Manchester discovered the girl had been unaccounted for since 2019. Her mother eventually reported her missing, and police arrested Adam Montgomery in January 2021, more than a year after the child was last seen alive.
Prosecutors said Harmony was last seen on December 7, 2019, the day they allege Montgomery killed her. Her body has never been recovered.
Jury selection for Montgomery's murder trial began on February 6, 2024, at Hillsborough County Superior Court in Manchester. Defense attorneys Caroline Smith and James Brooks represented Montgomery. Kayla Montgomery took the stand on February 9, 2024.
The jury convicted. Now the state must do it again, this time without the July assault charge sitting beside the murder count in the same proceeding.
Johnathon and Blair Miller, the adoptive parents of Harmony's brother Jamison, did not hold back after the ruling. They issued a joint statement expressing their reaction.
"We are absolutely disgusted by the decision of the New Hampshire Supreme Court. The reality is, more protection is in place for this monster than Harmony Montgomery ever received."
That statement captures a tension the legal system cannot easily resolve. The court's ruling is grounded in a bedrock constitutional principle: a defendant's right to a fair trial. The evidence of a prior assault was so strong it risked prejudicing the jury on a separate, weaker charge. Separating the two was legally sound.
But the Millers are not wrong about the broader picture. Harmony Montgomery slipped through every system designed to protect her. She vanished for years before anyone with authority noticed. Her father stands convicted of abusing her corpse and tampering with evidence. And now the one conviction that carried the weight of accountability for her death has been vacated on procedural grounds.
The retrial will test whether prosecutors can secure a murder conviction without the July assault evidence reinforcing their case in the jury's mind. The state has one witness linking Montgomery to the fatal December assault. Kayla Montgomery's testimony, secured through a plea deal, will again face credibility challenges from the defense.
Montgomery is not walking free. The 43.5-year sentence on his remaining convictions ensures that. But the murder charge carries a different kind of weight, for the family, for the public, and for a system that failed Harmony Montgomery at every turn before it finally tried to hold someone accountable.
Garrity's closing words from the Attorney General's Office set the tone for what lies ahead.
"We will continue our efforts to seek justice for Harmony Montgomery and all those who knew and loved her."
A little girl disappeared, and no one came looking for years. The least the system owes her now is getting the second trial right.
