At a glance
- Location: Manchester, New Hampshire, with ties to Lowell, Massachusetts
- Case period: Reported missing in late 2021; last confirmed sighting dated to late 2019
- Victim: A 5-year-old girl with a rare medical condition, described by relatives as resilient and loving
- Critical clue: Welfare benefits in the child’s name kept being claimed for months after she was last seen, even as her father gave police shifting, contradictory accounts of her whereabouts
For nearly two years, no teacher took attendance for her. No pediatrician saw her for a checkup. No neighbor could say for certain when they’d last laid eyes on her. When a Massachusetts mother finally walked into a police station in November 2021 and said she hadn’t heard from her five-year-old daughter in almost two years, investigators in Manchester, New Hampshire, were left asking a question that should never take this long to answer: where was Harmony Montgomery?
A Mother’s Long Wait
According to court records, Crystal Sorey, who lived in Lowell, Massachusetts, told police she had tried repeatedly to reach Harmony’s father, Adam Montgomery, over the preceding two years. Each time, she said, there was a new excuse. Investigators quickly discovered why tracking the family down was so difficult — Adam and his household had moved frequently, at times living out of a car. Records showed Harmony’s food stamps were still being claimed well after Sorey’s last contact with her, and Adam maintained, according to police, that his daughter was alive and in his care.
The backstory was already complicated. Sorey and Montgomery had separated before Harmony was born in June 2014. Adam was in prison at the time of her birth, having been sentenced for shooting a man during a drug deal gone wrong, according to court records. Harmony herself was born with a rare brain condition called holoprosencephaly; doctors initially told her mother she might not survive her first year and would likely be blind. She surpassed those expectations, family members said, regaining some of her eyesight and being described by those who knew her as happy and resilient.
Custody, Chaos and a Vanishing Address
After a stint in foster care, where relatives said she thrived, Harmony was placed with her father in February 2019 following a custody hearing that Sorey missed. Court records show she moved with Adam across state lines to Manchester, where he lived with his wife at the time, Kayla Montgomery, their two sons, and an uncle. Police had been called to the family’s home on Guilford Street roughly 30 times, according to authorities, and Adam’s uncle later reported seeing a black eye on Harmony and told child welfare workers that Adam admitted to “bashing her around the house.” Adam and Kayla denied the allegations at the time, and a caseworker’s visit in October 2019 found the children appeared healthy. It would be the last time anyone outside the immediate family reported seeing Harmony alive.
By the following winter, the family had lost their home and was living in a car. A caseworker who checked in on the family in January 2020 noted that Harmony was suddenly absent, and Adam claimed she had gone to live with her mother. Sorey never confirmed this when contacted, and, according to later reporting, no one from child protective services followed up for nearly two years.
The Confrontation
When police finally caught up with Adam Montgomery in early January 2022, body camera footage captured the encounter. Officers told him people were “wondering where Harmony is.” Adam claimed his daughter had been picked up by Sorey and an unknown man around Thanksgiving 2019 — a story that fell apart under basic questioning, since he could not explain where they had gone or how he’d lost contact with his own daughter for two years.
“I’m begging you to help me. Can you make me a promise? Like man to man, you tell me that she’s alive.”
Adam responded only by asking for a lawyer.
The Moment Investigators Had to Let Him Go
Despite the inconsistencies in his story, detectives did not yet have enough to hold Adam Montgomery on charges related to Harmony’s disappearance. Investigators seized a phone as evidence and warned him, according to body camera audio, that “it’s not going away — it’s going to get really big real quick.” But without a body, a crime scene, or a cooperating witness, police were forced to release him. It was a frustrating setback for detectives who, according to their own recorded conversations, already suspected the worst. “The kid was probably right at that age where” — as one investigator put it — a missing child could disappear from every system meant to track her, with no school enrollment and no medical records to flag her absence.
Adam was arrested days later, on January 4, 2022, but only on an assault charge tied to the 2019 abuse allegations his uncle had reported years earlier — not for Harmony’s disappearance itself.
A Break in the Case
The investigation gained momentum when Kayla Montgomery, Adam’s former wife, was arrested on welfare fraud charges for continuing to collect benefits in Harmony’s name. Investigators later caught her in a lie about the date she last saw Harmony, which led to a perjury charge. Facing that additional charge, Kayla agreed to a plea deal and began cooperating with prosecutors, giving detectives the account of what happened that they had lacked for two years.
According to her statements to investigators, the family was living out of a car in December 2019 when Adam Montgomery struck Harmony after she had a bathroom accident, causing her to lose consciousness. Kayla told investigators the family did not seek medical help and that Adam later found Harmony had died. What followed, according to her account, involved concealing and repeatedly relocating her remains over several months as the family moved between residences and a shelter.
Building the Case
Detectives said they corroborated parts of Kayla’s account by examining locations she described, reporting they found physical evidence, including DNA, consistent with her statements. Investigators also reviewed toll records and other data tied to a rented vehicle in the case. Based on the evidence gathered, prosecutors charged Adam Montgomery with second-degree murder, abuse of a corpse, falsifying physical evidence and witness tampering.
At trial in February 2024, jurors heard from Kayla, family members, friends and others connected to the investigation. Prosecutors played a recorded call in which Adam described the search for Harmony as “a waste of time.” Adam did not attend his own trial. He pleaded guilty to charges related to concealing Harmony’s death but maintained he was not responsible for her death itself, pointing instead to Kayla.
Where the Case Stands Today
Harmony Montgomery was legally declared dead in March 2024. Her remains have never been recovered. In 2025, the state of New Hampshire reached a $2 million settlement with Crystal Sorey after acknowledging failures in how child welfare officials handled the case, though the agreement released the state from further legal liability. In 2026, the New Hampshire Supreme Court overturned a conviction tied to the case, ruling that certain charges should not have been tried together, and ordered a new trial on the murder charge. Adam Montgomery remains incarcerated on separate charges connected to stolen firearms, and the legal proceedings surrounding Harmony’s death continue.
