Jurors found New Hampshire father Adam Montgomery guilty in the murder of his 5-year-old daughter Harmony after about six hours of deliberation over two days.

Prosecutors said during the two-week trial that after beating the helpless child, her father shot up opioids and ate fast food as she succumbed to her injuries in the back seat of his car.

"Today our thoughts are focused on the memory and legacy of Harmony Montgomery, a little girl who did not deserve the tragic fate that she suffered," New Hampshire Attorney General John Formella said after jurors returned the verdict. "Our hearts go out to Harmony’s family and all those who knew and loved her, and we hope today brings them some closure and peace."

After he realized she was dead, according to investigators, he concealed the body for months, heartlessly crushing her into a duffel bag and then a cooler and coating her with lime to reduce the odor of decomposition.

DAD BEAT DAUGHTER, THEN ATE FAST FOOD AND DID DRUGS AS SHE DIED IN BACK SEAT OF CAR, PROSECUTORS ALLEGE

Adam Montgomery enters the courtroom for jury selection ahead of his murder trial

Adam Montgomery enters the courtroom for jury selection ahead of his murder trial at Hillsborough County Superior Court in Manchester, New Hampshire, on Feb. 6. (David Lane/UNION LEADER POOL)

Eventually, he allegedly rented a U-haul truck and dumped her battered remains "like trash" somewhere outside Boston.

Then he said nothing for nearly two years. Harmony was finally reported missing when her frustrated noncustodial mother, Crystal Sorey, discovered the child had never been enrolled in school. Manchester police declared her a missing person in December 2022.

Montgomery, a 33-year-old violent felon and drug addict, had somehow been awarded custody of Harmony after his release from prison for shooting a drug dealer in the face, even as her brother's adoptive parents were actively trying to add her to their family.

"This is not a day we celebrate," her brother's adoptive parents, Blair and Johnathon Miller, said in a statement moments after jurors announced their verdict. "It is a day that only adds to the incredible pain and heartache that surrounds a little girl who was never given a chance."

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Harmony Montgomery is missing

Harmony Montgomery was reported missing two years after she was last seen. Her father was soon arrested on murder charges in connection with her 2019 disappearance, which they alleged followed a brutal beating in the back of his car. (National Center for Missing and Exploited Children)

Jamison, Harmony's brother, has been praying for her to return every night, they said.

"Jamison would go to the front door, hoping Harmony would find us," they said. "He would search for her in a park. As we now dig deep within our hearts to find the ability to offer forgiveness, we look to our son to give him the strength to fight off the demons that this tragedy has brought for a lifetime."

A Massachusetts watchdog agency later found that the state's child welfare system did not prioritize her "needs, well-being and safety" in placing her in her father's care.

"We remain grateful for the work of New Hampshire prosecutors, the New Hampshire Attorney General's Office, and the Manchester Police Department who made sure they fought for Harmony, especially when no one else ever did."

— Blair and Johnathon Miller

While collecting welfare on her behalf, Montgomery lived out of a car with his now-estranged wife Kayla, whom he is also accused of beating, and continued to use drugs, prosecutors said. Her testimony at trial is key evidence in the case.

As part of a plea deal, Kayla gave investigators damning testimony implicating her husband on charges that include second-degree murder, abusing a corpse and falsifying evidence. She told detectives that Adam kept Harmony's corpse for three months, repeatedly hiding it in new places before allegedly dumping it somewhere near Boston. Although the girl's body has not been recovered, investigators allegedly found her DNA in at least one location where he allegedly stowed it.

FATHER OF SLAIN NEW HAMPSHIRE GIRL ORCHESTRATED SAVAGE PLOT TO HIDE HEINOUS CRIME: PROSECUTORS

Kayla Montgomery, the estranged wife of Adam Montgomery, becomes emotional while being cross examined by Defense Attorney Caroline Smith during Adam Montgomery’s murder trial

Kayla Montgomery, the estranged wife of Adam Montgomery, becomes emotional while being cross-examined by Defense Attorney Caroline Smith during Adam's murder trial in Hillsborough County Court in Manchester, New Hampshire, on Feb. 12. (Jeffrey Hastings/Pool)

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On Dec. 7, 2019, the day investigators believe Harmony died, she had soiled herself in her sleep, prosecutors said. Her father allegedly beat her over the head viciously, telling his wife, "I think I really hurt her this time."

Then they went to a methadone clinic, picked up drugs, and got fast food, prosecutors said in their opening statement.

Kevin Montgomery gives testimony during the Adam Montgomery trial

Kevin Montgomery, the defendant's uncle, gives testimony during Adam Montgomery's trial in Hillsborough County Court  in Manchester, New Hampshire, on Feb. 9. Kevin Montgomery is one of the first witnesses to report alleged child abuse to authorities after claiming he saw Harmony with a black eye before she went missing. (Hans Pennink for Fox News Digital )

Little Harmony had another accident, prosecutors said. Her father turned around and beat her again. She died, moaning and gurgling, as prosecutors said he ate his food and shot up some drugs.

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He is already serving a minimum of 32 and a half years in prison for an unrelated firearms case — and has pleaded guilty to lesser charges in connection with Harmony's death.

Harmony's remains have not been found.