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, ruling that the trial court committed reversible error when it allowed the jury to hear testimony about Montgomery's prior violent acts. The decision, handed down this week, sends the case back for a new trial on the murder charge while leaving several other convictions intact.
Harmony Montgomery vanished from public view in late 2019, but her disappearance was not reported to authorities until late 2021, a gap that drew national attention and sharp criticism of the child welfare systems that lost track of her. Her body has never been found.
The ruling does not free Adam Montgomery. He remains convicted on charges of second-degree assault, falsifying physical evidence, and abuse of a corpse. But the reversal of the murder conviction strips away the centerpiece of the prosecution's case and forces the state to retry it, this time without certain evidence the high court found prejudicial.
At trial, prosecutors introduced evidence of Montgomery's prior bad acts, including allegations of past violence, to help establish a pattern of conduct toward Harmony. The defense objected, arguing the evidence was more prejudicial than probative. The trial court allowed it in.
The New Hampshire Supreme Court disagreed. In its opinion, the court found that the admission of prior-bad-act evidence violated New Hampshire Rule of Evidence 404(b), which generally bars evidence of other crimes or wrongs to prove a person acted in conformity with bad character. The court concluded the error was not harmless, meaning it likely influenced the jury's verdict on the murder charge.
The justices left Montgomery's other convictions undisturbed, signaling that the evidentiary problem was specific to the murder count rather than a flaw running through the entire trial.
The prosecution's task was unusual from the start. Without Harmony's remains, the state built its murder case on circumstantial evidence, witness testimony, and forensic indicators. Fox News reported that prosecutors argued Montgomery killed Harmony in December 2019 and then took steps to conceal her death, including disposing of evidence. The abuse-of-a-corpse and evidence-tampering convictions, which survived the appeal, reflect the jury's findings on those allegations.
Montgomery was also convicted of second-degree assault related to his treatment of Harmony. That conviction, too, stands.
The prior-bad-act evidence that the Supreme Court struck down had served a specific prosecutorial purpose: filling gaps in a case that lacked direct physical proof of the killing itself. Without it, the state will need to present a murder case that clears the 404(b) bar on retrial.
Harmony Montgomery was five years old when she was last seen alive in late 2019. She had been placed in her father's custody through a family court process, a decision that later drew intense scrutiny. For roughly two years, no agency, school, or mandated reporter flagged her absence.
It was not until December 2021 that the New Hampshire Division for Children, Youth and Families publicly acknowledged it had lost track of Harmony. The revelation triggered a missing-child investigation, a broader review of the state's child welfare protocols, and widespread public outrage.
Montgomery was arrested in early 2022 on charges unrelated to murder. The murder indictment followed as investigators pieced together evidence about what had happened to Harmony inside the Manchester, New Hampshire, home where she had lived with her father.
Kayla Montgomery, Adam's then-wife, was also charged in connection with the case. She pleaded guilty to welfare fraud and a theft charge related to continuing to collect benefits for Harmony after the child was no longer alive. Kayla Montgomery cooperated with prosecutors and testified at trial.
The Supreme Court's decision does not declare Montgomery innocent of murder. It holds that the trial was conducted with an evidentiary error serious enough to require a do-over on that specific charge.
For prosecutors, the retrial presents a concrete challenge. The state must prove second-degree murder beyond a reasonable doubt, again without a body, and now without the prior-bad-act evidence the first jury heard. The Hillsborough County Attorney's office has not publicly detailed its timeline for retrial proceedings.
Montgomery's defense team had argued on appeal that the prior-bad-act testimony was the linchpin that pushed the jury toward conviction on the murder count. The Supreme Court's ruling validates that argument, at least to the extent that the justices found the error was not harmless.
Investigators have not publicly confirmed whether any new evidence has emerged since the original trial that could strengthen or alter the prosecution's case on retrial.
Even with the murder conviction overturned, Montgomery faces significant prison time on the surviving charges. Second-degree assault, falsifying physical evidence, and abuse of a corpse each carry their own sentencing ranges under New Hampshire law.
The assault conviction relates to physical harm inflicted on Harmony before her death. The evidence-tampering and corpse-abuse convictions speak to what prosecutors say Montgomery did after she died. Together, they paint a picture the jury accepted: that Montgomery harmed his daughter and then tried to cover it up.
Sentencing on those counts may proceed independently of the murder retrial, though the trial court has discretion over scheduling.
Harmony Montgomery's case became a flashpoint for criticism of New Hampshire's child protective services. A five-year-old child fell off every institutional radar for two years. No welfare check caught the gap. No school enrollment flag was raised.
State officials launched internal reviews after Harmony's disappearance became public. Legislative hearings followed. Reforms to inter-agency communication and child welfare tracking were proposed, though the scope and implementation of those changes remain subjects of ongoing debate in Concord.
The Supreme Court's ruling reopens a wound that many in New Hampshire hoped the original conviction had begun to close. A retrial means more proceedings, more testimony, and more public attention to a case that exposed deep failures in the systems meant to protect children.
The case now returns to the Hillsborough County Superior Court. Prosecutors must decide how to structure a second murder trial within the evidentiary boundaries the Supreme Court has drawn. Defense attorneys will likely press any additional appellate arguments that survived the first round.
Authorities have not said whether the search for Harmony's remains continues. Her body's location remains unknown.
Montgomery remains in custody on the surviving convictions. No bail determination on the murder charge has been publicly announced in the wake of the reversal.
When a court tells prosecutors they cut corners on evidence rules, even in a case involving a dead child no one reported missing for two years, the law demands they go back and get it right. Whether the state can secure a second conviction without the evidence the justices excluded will test both the prosecution's case and the public's faith that the system can deliver accountability for Harmony Montgomery.
