CONCORD, N.H. (AP) — The father of Harmony Montgomery, a New Hampshire girl who disappeared in 2019 at age 5 but was not reported missing until late last year, has been arrested on a charge of second-degree murder, authorities said Monday.

He is accused of repeatedly striking her in the head with a closed fist that December.

Other counts against Adam Montgomery, 32, include falsifying physical evidence and abuse of a corpse between December 2019 and March 2020. Authorities did not say whether the girl's body had been found.

Montgomery also is charged with tampering with a witness by attempting to cause his wife and Harmony's stepmother, Kayla Montgomery, to provide false testimony. He is scheduled to be arraigned Tuesday in Manchester.

An attorney for Adam Montgomery did not immediately comment.

“I do want to again express my deepest sympathies to Harmony’s family, friends and loved ones," state Attorney General John Formella said at the news conference in Manchester. "We understand that today’s news, while significant for purposes of this investigation, is yet another difficult moment for those who loved Harmony and those who have followed this case.”

In August, authorities said the case had become a homicide investigation. They said they believe Harmony was killed in Manchester, the state's largest city, in early December 2019.

Police first became aware that Harmony might be missing when they received a call from the girl’s mother, Crystal Sorey, in November. She had been unsuccessfully trying to locate the girl for months, police said.

Police said they contacted Adam Montgomery, who had custody of Harmony, and other family members by the end of December. According to court documents, police told him that Harmony had not been seen in more than two years and there was concern over whether she was still alive.

Harmony’s father and stepmother, who have since pleaded not guilty to charges related to her well-being, told police that Adam brought Harmony to be with Sorey in Massachusetts around Thanksgiving 2019. Sorey said she last saw her daughter during a phone video conversation around Easter that year.

“I am in shock at this point, it hasn't really hit me yet," Sorey said in a text message to The Associated Press. She added that “nobody wanted to listen to me, this could've all been avoided, but now we're faced with the biggest battle my family will ever face!"

Adam Montgomery was in court last month as his lawyers argued that some of the statements he made to police should be suppressed. They said he told police multiple times that “I’ve got nothing else to say” when questioned further about his daughter's whereabouts and said he didn’t want to talk to them, yet police kept asking him questions.

He faces a trial next month in an unrelated case on stolen weapons charges.

Bail for Kayla Montgomery was recently revoked after she didn’t show up at a hearing on charges against her, including that she lied to state health officials about having Harmony Montgomery in her care.

Harmony's case has prompted an outpouring of support, including vigils and social media sites. Police offered cash rewards for information and dedicated a 24-hour tip line to the case.

“I ask that in memory of Harmony that we all make every effort to do something nice for a child today," Manchester Police Chief Allen Aldenberg said at the news conference. He added, “Just take a few moments out of your day to say something nice to a child, give him or her a hug, some special words of encouragement."