(NewsNation) — The search for a missing 8-year-old New Hampshire girl has shifted to a homicide investigation, local authorities announced on Thursday.

“Harmony Montgomery was murdered in Manchester in early of December 2019,” New Hampshire Attorney General John Formella reported in a presser Thursday.

Formella went on to say that he, along with the Manchester Police Department, the U.S. Marshall Service, the FBI, as well as other law enforcement partners came to this conclusion through new leads.

“While Harmony’s remains have not yet been located, we do have multiple sources of investigative information — including just recently confirmed biological evidence — that have led us to this difficult and tragic conclusion.”

“As a result, today I am announcing that this is now officially a homicide investigation and that our investigators will continue to seek justice and look into the circumstances of Harmony’s murder and search for her remains,” Formella continued.

Thursday’s update is the latest in what was previously a missing person case, as Harmony Montgomery was last seen in 2019, when she was 5.

Formella’s update is also a progression from investigators turning their attention to the second-floor apartment where her father, Adam Montgomery, and stepmother, Kayla Montgomery, once lived in Manchester, New Hampshire just this past June.

Mr. Montgomery was awarded custody of Harmony in 2019 by a Massachusetts judge. The court did not require any further review of Adam or of his home — which was later discovered to be without electricity.

In September 2021, New Hampshire’s division of Youth and Family Services was contacted by someone raising concerns about Harmony’s whereabouts. Around this time, Family Services confirmed Harmony was never registered to attend school.

Adam and Harmony’s stepmother Kayla are behind bars on charges connected to her disappearance.

They are not cooperating in the investigation, according to police.

“We understand that this is truly devastating news for Harmony’s family, friends and loved ones,” Formella said. “Our hearts go out to them.”

“This is also devastating news for the city of Manchester, for our state and all who have followed this story. Our work now turns to getting justice for Harmony and all those who loved her,” he continued.

A tip line is open for those who have information about Harmony. Call or text (603) 203-6060