CONCORD, NH – The New Hampshire Supreme Court overturned the second-degree murder conviction of Adam Montgomery on Thursday, agreeing with the defense that an unrelated assault charge should not have been prosecuted at the same time.
The court issued the ruling on Thursday.
Montgomery was convicted of murdering his 5-year-old daughter Harmony in 2019 and then secreting her body for months before discarding it in an unknown location. The child’s remains have never been found.
“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,” New Hampshire Attorney General John Formella said. “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.
“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.”
Manchester Police Chief Peter Marr said he was disappointed at the ruling.
“While I am disappointed in the Supreme Court’s decision, this is the process at work,” he said. “We have full faith and confidence in the New Hampshire Attorney General’s Office. I have no doubt they are carefully reviewing today’s decision and working together to determine the appropriate next steps. Nothing about today’s ruling changes the tragic loss of a young child whose life mattered deeply, or how much this community cared about Harmony. Her memory continues to resonate throughout Manchester, and our focus remains on seeking justice for her.”
In 2024, Montgomery was convicted of second-degree murder for the beating death of Harmony and sentenced to 56 years to life in prison.
The Supreme Court reversed that conviction, but upheld his convictions for second-degree assault, falsifying physical evidence, witness tampering and abuse of a corpse. The justices said “the best interests of justice required severance of the charges.”
According to the court ruling, the jury was asked to determine which of the two adults who were with the victim on Dec. 6 and 7, 2019 — Adam or his wife Kayla — killed her. While the jury heard no evidence that Kayla had ever physically assaulted Harmony, it heard evidence from multiple witnesses that Adam physically assaulted Harmony in July 2019.
“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. See Bean v. Calderon, 163 F.3d 1073, 1083 (9th Cir. 1998) (concluding that joinder of charges arising from separate incidents allowed the jury to draw an impermissible inference of criminal propensity which “in turn, allowed the jury to rely upon” evidence in the stronger case “to strengthen the otherwise weak case” on other offenses). We conclude that, under these circumstances, trying the second-degree assault and second-degree murder charges in a single trial jeopardized the defendant’s right to a fair trial,” said the justices in overturning the murder conviction.
Senior Assistant Appellate Defender Pamela E. Phelan argued the case before Supreme Court on Oct. 15, 2025. She maintained Montgomery should have been tried separately on the assault charge. Montgomery was accused of blackening Harmony’s eye in the summer of 2019, months before he murdered her.
Assistant Attorney General Sam Gonyea argued that “any error with respect to joinder was also harmless as to the second degree murder charge because the ‘state’s case and the evidence of the defendant’s guilt (were) overwhelming.”
The Supreme Court justices disagreed.
“We conclude that the misjoinder of offenses was not harmless as to the homicide charge. Accordingly, we reverse the defendant’s conviction of second-degree murder,” justices wrote.
Harmony was missing for close to two years before law enforcement learned of it from her biological mother.
A Massachusetts judge gave Montgomery custody of Harmony in February 2019 and she went to live with him, his wife and their two children. At the time, Harmony’s mother, Crystal Sorey, was in rehab.
The Montgomery family lived in his grandmother’s Manchester house, along with Montgomery’s uncle.
The uncle returned home in July 2019 from a three-week trip and saw Harmony with a black eye. He asked Harmony what she had done and Adam Montgomery answered, “She didn’t do anything. I bashed her around the f**king house.” The uncle testified Montgomery told him he “put Harmony in charge to watch her five-month-old brother while he used the bathroom. When he returned, he found Harmony with her hands over the baby’s mouth and “his lips were supposedly blue.”
The Supreme Court, in its ruling, summarized the evidence in the case:
On Nov. 27, 2019, the family was evicted from their home and they were living out of their car.
Although Harmony was toilet trained before she was three years old, she started to have accidents in the car. When Harmony soiled her pants, an angry Montgomery would hit her in the face or on her leg or hand.
On Dec. 7, 2019, Harmony had an accident early in the morning and Montgomery repeatedly punched her in the head. Later that morning, the family drove to a methadone clinic where Kayla and Adam took turns going inside while the other stayed in the car with the children.
When Adam returned to the car, he realized Harmony had had another accident and started yelling at her and hitting her in the head repeatedly.
From the methadone clinic, Adam drove to Burger King. While he was driving, Harmony was in the back seat crying and making a strange, moaning-like noise. Adam told her to shut up, and at each red light at which they stopped, he reached back and repeatedly punched Harmony in the head. He stopped hitting her when they got to Burger King. With the final punch, he said in a scared voice that he felt something and thought he really hurt her this time.
Later that day, the family’s car broke down at a traffic light and they had to abandon it. As Adam and Kayla were getting the children out of the car, Harmony did not respond and they realized she had died. Adam got a duffel bag from the trunk, put her body in it, and brought it back to the friend’s apartment complex, where he put it in a snow bank.
Following the loss of their car, the family stayed in a friend’s car, then with Kayla’s mother, and then, from Dec. 30, 2019 through Feb. 20, 2020 at the Families in Transition (FIT) shelter in Manchester. Adam brought the duffel bag containing Harmony’s body to each place where they stayed.
At FIT, he put the duffel bag in the ceiling vent in their room. When Harmony’s body began to smell and leak fluid, he put it into garbage bags which he then stuffed into a diaper bag. The defendant worked at a restaurant at that time and would store the bag in the restaurant’s freezer while he was there.
The family moved from FIT to an apartment in Manchester. There, Adam kept Harmony’s body in the apartment’s freezer. He began discussing getting rid of Harmony’s body and devised a plan to dismember her and use lime, which he believed would hasten decomposition of the body.
On Feb. 26, 2020, the defendant withdrew cash from an ATM and purchased lime, an angle grinder, a blade, and a battery. At some point thereafter, he thawed the body in the bathtub at the apartment and had Kayla help remove Harmony’s clothing. He had a large bag of lime and spent several hours in the bathroom with Harmony’s body. When he finished, he put Harmony’s body back in the diaper bag and put the bag back in the freezer.
On March 3, 2020, Adam and Kayla stayed at an Econo Lodge with a friend of Adam’s and the friend’s girlfriend. Adam had asked the friend to rent a U-Haul for him because “he needed to move stuff.” That evening, the friend arranged the rental. Back at the hotel, the friend and Adam went outside to smoke a cigarette and Adam began pacing back and forth, repeating “I f**ked up.”
Adam left the hotel in the U-Haul in the middle of the night. He took the diaper bag containing the victim’s body with him and returned without it, telling Kayla he “got rid of her.”
After he killed Harmony, Adam began telling people that he had returned Harmony to her mother in Massachusetts after Thanksgiving in 2019. Crystal Sorey, Harmony’s mother, however, had not seen her daughter since April 2019. Storey tried to contact Adallm and Kayla but was unsuccessful. By Dec. 2021, Sorey had reached out to state and local agencies and officials to try to find her daughter. At that point, law enforcement became involved in the search for Harmony.