New Hampshire’s Supreme Court on Thursday overturned Adam Montgomery’s second-degree murder conviction in the death of his daughter, Harmony Montgomery, throwing out the 56-years-to-life sentence tied to the state’s most serious count against him. The justices said a procedural flaw in the way the case was tried required reversal.

The ruling is the latest major turn in a case that has drawn national attention because it centered on the death of a 5-year-old girl whose disappearance went largely unnoticed for two years. Harmony vanished in 2019, and her mother, Crystal Sorey, came to Manchester in late 2021 to search for the child herself after losing custody in 2018.

At trial in 2024, Montgomery was convicted of second-degree murder for recklessly causing his daughter’s death and of second-degree assault over an earlier episode of physical abuse. The court said those charges should not have been kept together in one case because doing so jeopardized his right to a fair trial. The judges reversed the murder conviction, but they left standing the rest of the verdicts: assault, falsifying physical evidence, witness tampering and abusing his daughter’s corpse.

That distinction matters because Montgomery is not leaving prison. He is still serving the decades-long sentence he received in 2023 on unrelated firearms offenses, and he remains convicted on the other charges tied to Harmony’s death. The murder reversal removes the life sentence imposed in that trial, but it does not erase the broader findings that he hid the child’s remains and failed to report her death.

The murder case had rested in part on testimony from his estranged wife, Kayla Montgomery, and on evidence that he concealed Harmony’s body in a series of locations, including the ceiling of a homeless shelter and a walk-in freezer at the pizza shop where he worked for about a month. Harmony’s remains still have not been found, and Adam Montgomery never disclosed where they were.

In a statement accompanying the ruling, Justice Pamela E. Phelan said justice depends on a fair and just trial, and that a trial not conducted on those principles does not do justice either to an accused person or to victims. The court’s decision leaves prosecutors with a high-profile conviction undone and a narrower case still intact, but it does not answer the next question in the fight over Harmony’s death: whether the state will try again on the murder charge.