‘I really hurt her’: Affidavit reveals horrifying new details in murder of Harmony Montgomery

MANCHESTER, N.H. — Adam Montgomery beat his daughter, Harmony Montgomery, to death in a fit of rage after she had a “bathroom accident” in the car the family was living in before moving her lifeless body from one hiding place to the next in an effort to conceal the stench of her decaying remains, according to an affidavit that revealed horrifying new details about the young girl’s death.

Adam repeatedly struck Harmony, who was 5 at the time, in the head in frustration over the accident in December 2019, Adam’s estranged wife, Kayla Montgomery, told Manchester police detectives during her first proffer interview.

“Kayla described that Harmony was in the rear seat on the passenger side, and while Adam was driving he turned his body and delivered sets of three-to-four blows with a closed fist to Harmony’s face/head on three separate occasions over the course of a few minutes,” a detective stated in the affidavit. “Kayla stated that after the final blow, Adam said words to the effect of that he felt something or heard something when he hit Harmony, and, ‘I think I really hurt her this time. I think I did something.’”

After the assault, Harmony reportedly began making a moaning type of noise as the family drove to Burger King, which went on for roughly five minutes and then stopped.

“At no time did anyone stop or get Harmony medical attention as the result of this assault. Kayla said this happened in the morning while the family was on their way to the Burger King on Route 3 in Manchester,” the detective explained. “Afterward the family returned to the parking lot of the Colonial Village apartments. The family stayed at Colonial Village for approximately 20 minutes, during which time no one checked on Harmony.”

Harmony died in the car a short while later, at which point Adam and Kayla placed her “lifeless” body into an Under Armour duffle bag before transferring her body into a red cooler with a white top, the affidavit showed.

“Kayla explained how Harmony’s body was moved to various locations over the course of the next several months. She stated that after living in the Colonial Village parking lot, they then moved in with her mother at 258 Dubuque Street,” the detective added. “Kayla said when they arrived at the residence, Harmony’s body, which was still in a duffle bag, was placed inside a red cooler with a white top in the common hallway of the apartment building. She stated that the body was left there the whole time the family stayed there, until the end of December 2019.”

Harmony’s body was also said to be placed inside garbage bags and a refrigerator after her death.

In an interview in June 2022, Kayla alleged that Adam placed the duffle bag with Harmony’s remains in a ceiling vent in a bedroom when they later moved into a “Families in Transition” shelter on Lake Street.

“Kayla stated that during this time, there was liquid coming from the bag containing Harmony’s dead body, and there was an odor,” the detective explained. “She said Adam placed a trash bag around the bag to keep it from leaking.”

Detectives later searched the ceiling vent, located a large area of staining, and submitted that section for DNA testing.

“The DNA profile obtained from the sample is approximately 1.1 trillion times more probable if the sample originated from Harmony Montgomery and one unknown person than if it originated from two unknown persons,” detectives stated.

Kayla said that when they later moved to Union Street in February 2020, Harmony’s remains were transferred into a refrigerator. At a subsequent point in time, Adam allegedly moved his daughter’s remains into a Catholic Medical Center maternity bag while spending hours in the bathroom with the shower running.

“This bag was much smaller than the Under Armour duffle bag, and it would not likely fit Harmony’s body unless it was dismembered or grossly distorted,” detectives stated. “Kayla described an odor coming from the bathroom and saw steam coming from the bathroom when Adam would open the door. Kayla recalled the scent of cleaning supplies in the bathroom when Adam had finished up.”

Adam later brought that CMC bag to his place of work, the Portland Pie Company restaurant on Elm Street, where he stored Harmony’s remains in a walk-in cooler for a “week or so,” Kayla told detectives.

A Portland Pie Company worker questioned during the investigation said he recalled seeing the CMC bag in the cooler on a couple of occasions on both the floor and shelf but never asked Montgomery about it since he knew he had children.

The documents indicated that Adam later brought Harmony back to their Union Street apartment, where he allegedly dumped her frozen remains into the tub so he could use a bag of lime to “help with the decomposition” of her body.

“Adam had a difficult time fitting Harmony’s body back into the CMC maternity bag. Harmony’s body was frozen,” Kayla recalled before admitting to helping Adam cut Harmony’s clothes off of her body to make her fit into the bag.

In either March or May of 2020, Adam rented a U-Haul and during the overnight hours, made a trip to an unknown destination to dispose of Harmony’s dead body, according to Kayla.

“Kayla stated that around the time that Adam disposed of Harmony’s body, they stayed in the Econo Lodge or Comfort Inn,” detectives said. “Kayla saw the U-Haul from the hotel window, and she described it as a van with a large “19.99″ on the back, which is consistent with the lettering/numbering on a U-Haul rental vehicle.”

When he returned to the hotel, Kayla said Adam seemed very tired, and that he said words to the effect of “it’s done.”

In April, the search for Harmony’s remains brought investigators to the wetlands along Lynn Marsh Road in Revere. That search ultimately ended without police saying if they found any evidence related to Harmony.

Harmony’s body has never been found.

Earlier this month, Adam was found guilty of all charges in his firearms trial.

Adam is facing charges of second-degree murder, tampering with witnesses and informants, falsifying physical evidence, and abuse of a corpse in his daughter’s death.

The murder trial could begin later this year.

Boston 25′s Bob Ward gives thoughts about the Harmony Montgomery case now that Adam Montgomery’s murder affidavit is unsealed.

This is a developing story. Check back for updates as more information becomes available.

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