The New Hampshire Supreme Court has overturned 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 second-degree assault charge in a single proceeding denied him a fair trial. The state's Attorney General's Office says it will take him back to court.
Montgomery still faces a 43.5-year sentence on related convictions the court left intact, abuse of a corpse, tampering with evidence, and assault, but the central charge, that he killed his own child, must now be tried again before a new jury.
For the adoptive parents of Harmony's brother, the ruling landed like a second blow. Johnathon and Blair Miller, who adopted Harmony's brother Jamison, did not hold back.
"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 raw sentiment captures a tension the legal system forces on cases like this one: the constitutional rights of the accused versus the plain facts of a dead child whose body has never been found.
The ruling, first reported by Fox News Digital, hinged on the risk of prejudicial spillover between two charges tried together. The court acknowledged that the state's evidence on the assault charge was strong. Three witnesses saw Harmony with a black eye in July 2019. Four witnesses, including two who saw the black eye, testified that Montgomery admitted striking her.
But that strength became the problem. The court found a "significant risk" that jurors drew an impermissible inference: because Montgomery had struck his daughter in the head before, he must have been the one who fatally struck her in December.
The court's opinion stated the concern plainly:
"Thus, 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."
Only one witness, Kayla Montgomery, Adam's then-wife and Harmony's stepmother, linked him to the December assault that investigators believe killed the girl. The defense had challenged Kayla Montgomery's credibility, noting she had received a deal from prosecutors in exchange for her testimony. Defense attorneys also tried to shift blame to her, arguing she was the last person to see Harmony alive.
The court noted that jurors heard no evidence Kayla Montgomery had ever physically assaulted Harmony. But they heard from multiple witnesses that Adam Montgomery had.
That asymmetry, the court concluded, made a joint trial unfair.
The facts behind the legal arguments are brutal. Prosecutors said Harmony soiled herself in her sleep on December 7, 2019. Her father allegedly beat her over the head. He then allegedly told Kayla Montgomery, "I think I really hurt her this time."
Harmony was never seen again.
For roughly two years, no one in the system noticed. Investigators in Manchester, New Hampshire, eventually discovered the girl had been unaccounted for since 2019. Her mother, who did not have custody and was no longer involved with Adam Montgomery, reported Harmony missing. Police arrested Montgomery in January 2021.
Jury selection for his murder trial began on February 6, 2024, at Hillsborough County Superior Court in Manchester. Kayla Montgomery testified against him three days later. The jury convicted him.
Now that conviction is gone.
Michael Garrity, spokesperson for New Hampshire Attorney General John Formella, told Fox News Digital on Thursday that the state intends to bring Montgomery back to trial 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 overturned conviction does not erase everything else. Montgomery remains convicted of multiple serious felonies connected to Harmony's death, plus separate firearms offenses previously upheld on appeal. His 43.5-year sentence on those charges stands.
"We remain confident in the facts of this case, the evidence presented, and the exceptional work of our prosecutors, investigators, and law enforcement partners. We will continue our efforts to seek justice for Harmony Montgomery and all those who knew and loved her."
That confidence will be tested. A second trial means re-presenting the case, this time without the assault evidence sitting alongside the murder charge in front of the same jury. Prosecutors will need to convince twelve new jurors based on what remains, with Kayla Montgomery's testimony again at the center and her credibility again under attack.
One detail in the ruling deserves attention. Montgomery's own defense team initially requested that the charges be tried together. Only after receiving additional evidence did the defense try to sever the cases, and that motion was denied by the lower court. The Supreme Court overturned the conviction anyway, finding that the trial judge should have recognized the prejudicial risk regardless of which side originally sought joinder.
That procedural history will frustrate anyone who believes the system should not reward a defendant for a strategic choice his own lawyers made. But the court's reasoning rests on constitutional ground: the right to a fair trial does not evaporate because a defense attorney made an earlier tactical decision that turned out to cut against his client.
Whether one agrees with the ruling or not, the practical result is clear. A man convicted of killing his five-year-old daughter, a child whose remains have never been recovered, will get another chance to walk on the most serious charge against him.
Harmony Montgomery's body has not been found. The court's ruling does not address where investigators believe her remains may be. The terms of Kayla Montgomery's deal with prosecutors remain unspecified in public reporting. And no timeline has been set for the retrial.
The case has drawn national attention since Harmony's disappearance first came to light, a little girl who fell through every crack the system is supposed to fill. Her father, convicted of hiding her body and tampering with evidence, remains behind bars. But the charge that names what he allegedly did to her, murder, now hangs in legal limbo.
Harmony Montgomery deserved protection from the adults and institutions around her. She didn't get it in life. The least the system owes her now is a second prosecution that gets the job done right.