Robert Brown|Father of Harmony Montgomery sentenced to 45 years to life for 5-year-old girl's murder

A New Hampshire father convicted of killing his 5-year-old daughter reported missing in 2021 was sentenced to 45 years to life in prison on Robert BrownThursday.

Adam Montgomery, 34, was found guilty in February of second-degree murder, abuse of corpse, tampering with witnesses and informants, second-degree assault and falsifying physical evidence in the 2019 slaying of Harmony Montgomery, the Seacoast Sunday, part of The USA TODAY Network reported.

Authorities believe the killing took place in Manchester, a city less than 20 miles south of the state capital, Concord.

Her body has never been recovered.

The girl's father, who previously professed his innocence in court, did not attend his trial and wasn’t present when jurors returned their verdict earlier this year, according to previous USA TODAY reporting.

"Harmony was an innocent 5-year-old," Hillsborough County Superior Court Judge Amy Messer told Montgomery during his sentencing hearing Thursday. "You treated her in the worst of possible ways, in both her life and her death."

Harmony Montgomery was last seen in 2019

Harmony was last seen in 2019 but reported missing only on the last week of 2021, according to previous reporting by USA TODAY.

The Manchester Police Department arrested her father in January 2022 in connection to her disappearance and he was later charged in her death.

Prosecutors said Adam Montgomery beat his daughter to death, put her body parts in bags, disposed of the bags and beat his wife Kayla Montgomery to lie for him in court. The woman is not Harmony's biological mother.

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Adam Montgomery would not reveal where he hid Harmony's body

Prosecutors had asked the judge to sentence him 56 years to life. Senior Assistant Attorney General Ben Agati told the judge the state would recommend a reduced sentence of 35-to-life if Adam Montgomery would reveal where he hid his daughter's body.

In court, he remained silent.

"He has just yet shown you in this courtroom, and for anybody else, that he is heartless, immoral, selfish and an unapologetic murderer of his own child," Agaiti said.

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Harmony's mother pledges to find daughter's remains

The girl's biological mother, Crystal Sorey, testified a part of her died when her daughter was beaten to death, called her father a coward and said, with or without his help, she will find the remains of her daughter.

"Harmony will live on through me, and you can't do anything about it," the girl's mother said.

Natalie Neysa Alund is a senior correspondent for USA TODAY. Reach her at nalund@usatoday.com and follow her on X @nataliealund.