Search for missing New Hampshire girl Harmony Montgomery is now a homicide investigation

A "sweet and innocent" New Hampshire girl who has been missing for nearly three years is a homicide victim, although her remains have yet to be found, authorities said Thursday.

Harmony Montgomery was most likely killed in Manchester in early December 2019, New Hampshire Attorney General John Formella told reporters. She was 5 years old at the time.

Formella, the state's top prosecutor, said investigators have uncovered "biological evidence" that has "led us to this difficult and tragic conclusion."

"This is now officially a homicide investigation," Formella said. "Our investigators will continue to seek justice and look into the circumstances of Harmony's murder and search for her remains."

Formella and Manchester Police Chief Allen Aldenberg did not take questions or elaborate on the evidence that led them to declare Harmony's death.

Thursday's development comes more than seven months after police in Manchester said they first learned that Harmony had not been seen for two years.

The girl has not been seen since late 2019, but police said they learned she was missing only in December.

Aldenberg called her a "sweet and innocent 8-year-old girl."

Authorities appealed for the public's help in finding her remains and identifying her killer.

“The time is now. Time to step up and do the right thing and make the call to that tip line," Aldenberg said. "Harmony's a sweet and innocent child who deserves to be brought home to her family and friends."

Harmony was in the custody of her father, Adam Montgomery, when she was last seen in late November 2019, New Hampshire law enforcement officials have said.

Adam Montgomery and his wife, Kayla, who is not Harmony's mother, have both been arrested and charged, but not in direct connection with the girl's disappearance. Both have pleaded not guilty.

Adam Montgomery was charged with assault after he was alleged to have told an uncle that he had given Harmony a black eye in June 2019, according to court documents.

Kayla Montgomery has been accused of welfare fraud and collecting more than $1,500 in food stamp benefits for Harmony, even though the girl was no longer living at their home.

Harmony was born in Massachusetts and spent much of her life in the custody of that state’s Department of Children and Families, according to a report from the state Office of the Child Advocate.

Harmony's mother, Crystal Sorey, and father had substance abuse issues, according to the child advocate agency. In February 2019, a court awarded custody to Adam Montgomery, who lived in New Hampshire.

Sorey contacted Manchester police in November and said that she was sober but that Adam Montgomery had been blocking all her attempts at communication and that the last time she had seen her daughter was on a video call in April 2019, according to a police affidavit.

Harmony, Adam and Kayla Montgomery and the couple's two other children were evicted from a Manchester home on Nov. 27, 2019, and people reported seeing Harmony with them in the following days, the New Hampshire attorney general's office has said.

But by early December, it appeared Harmony was no longer with them, the office said.

According to court documents, Kayla Montgomery told investigators that Adam Montgomery informed her in late 2019 that Harmony was going to live with her mother.

Adam Montgomery told police that Sorey picked the girl up in Manchester, according to a police affidavit filed in his case.

Sorey has said that she had been trying to find her daughter since April 2019 and that she reached out to nearby schools and the New Hampshire Division of Children, Youth and Families. She has not been accused of any wrongdoing.

Since late December, police and others have pleaded for information, a reward of $60,000 was offered and volunteers joined in looking for any clues.