When Manchester police publicly declared 7-year-old Harmony Montgomery a missing child last week, they also revealed she’d been unaccounted for since late November 2019.

Many people are asking how this is possible?

The agencies that take care of at-risk children are swamped, and their resources stretched thin, experts say. And COVID-19 has a double impact on kids in foster care with school shutdowns and social distancing. 

Adam Montgomery, whose criminal history of violence included pleading guilty to shooting a man in a drug-fueled robbery in 2014, nevertheless secured sole custody of his daughter Harmony on Feb. 22, 2019, and moved her to New Hampshire. Her mother, Crystal Sorey, had to surrender Harmony to the state of Massachusetts in the summer of 2018.

Harmony Montgomery

Harmony Montgomery was placed in her father's custody just months before she was last seen. He had served time in connection with a violent drug robbery and was later accused of domestic violence by her stepmom. (Manchester Police)

MISSING HARMONY MONTGOMERY: TIMELINE OF NEW HAMPSHIRE GIRL'S DISAPPEARANCE

Between July 1 and 22 of 2019, Montgomery allegedly punched the girl, who was 5 at the time with visual impairments that included blindness in her right eye, in the face.

At least two family members — Harmony’s stepmom Kayla Montgomery and her father’s uncle Kevin Montgomery — later told police they saw her with a black eye. Her own uncle, Michael Montgomery, said he heard about it. But none of them reported it to police until last week, when Manchester detectives started demanding answers.

Child welfare agencies in both states declined to comment, citing privacy concerns.

Adam and Harmony Montgomery

Left: Adam Montgomery, who police arrested this week on child abuse and endangerment charges in connection with an alleged assault on his daughter from 2019 and her disappearance. Right: Missing Harmony Montgomery (Manchester Police)

Numerous social workers and child advocacy organizations declined to comment for this story. Some said they feared retaliation. Others said there were ethical concerns about weighing in on a child welfare case without firsthand knowledge of its details. But others, speaking under the condition of anonymity, questioned why a special needs child like Harmony, who is blind in one eye, was not enrolled in school or assigned a dedicated caseworker while her stepmother was collecting food stamps in her name.

MISSING HARMONY MONTGOMERY: DEADBEAT DAD'S MOTHER-IN-LAW SOUGHT RESTRAINING ORDER OVER SUMMER

Police took action after Harmony’s noncustodial biological mother, Sorey, officially reported the girl missing Nov. 18 2021, telling them Adam Montgomery had been ignoring her for more than two years as she tried contacting him and her daughter to arrange a reunion between Harmony and her younger brother after the boy had been adopted.

Sorey also reported struggling with New Hampshire’s Division of Children, Youth and Families during that time, calling them regularly but unable to reach her daughter.

Kayla Montgomery

Kayla Montgomery, 31, was arrested in Manchester, N.H., and charged with welfare fraud. (Manchester Police Department)

The police report came after Sorey learned from school officials that Harmony had never been enrolled in Manchester, despite having purportedly lived there from the age of 5 to 7.

During that same span of time, school closures and other coronavirus precautions made it easy to hide out, according to Betsy Brantner Smith, a spokesperson for the National Police Association and retired sergeant whose 29-year career included investigating crimes against children in Illinois.

MISSING HARMONY MONTGOMERY: DAD ACCUSED OF GIVING PARTIALLY BLIND DAUGHTER BLACK EYE IN 2019, OTHER ABUSE

"COVID and the lockdowns were likely very unhelpful in this situation," she told Fox News Digital Friday. "This is one of the reasons that school shutdowns are so dangerous for children, because very often, school is the only place for a child to be safe."

In some circumstances, it may be the only time an at-risk child is ever around a responsible adult, Brantner Smith added, like a teacher, guidance counselor or other district employee. And resources for state agencies are scant and stretched thin.

Brantner Smith said local police departments should be given more investigative authority over some of these cases, noting that shortly after Manchester police joined the search for Harmony, the adults who were supposed to be taking care of her were behind bars.

Harmony Montgomery

Harmony, now 7, was reported missing last week after last being seen 2 years ago. (Manchester Police Department)

MISSING HARMONY MONTGOMERY: ADOPTIVE PARENTS' PUSH TO REUNITE SEPARATED SIBLINGS TRIGGERED SUSPICIONS

"These cases are horrific to think about," Brantner Smith said. "But American law enforcement is ready to deal with it. We want to deal with it. We want to stop it, and we want to protect our children. But there are some very, very broken systems in this country."

Callahan Walsh, spokesperson for the National Center for Missing & Exploited Children, said coronavirus shutdowns could have made it easy for an abusive parent to lay low. 

"With corona and with lockdowns, it’s been kind of easy for people to sort of just hide out, keep a low profile, stay under the radar," said Walsh, who is also the co-host of "In Pursuit with John Walsh," streaming on Discovery+. 

Manchester Police Chief Allen Aldenberg

Manchester Police Chief Allen Aldenberg delivers a news briefing on the search for missing 7-year-old Harmony Montgomery. (Manchester Police)

He said the fact no other family members reported her missing may have been a "bystander effect."

"Everybody thought she was safe and assumed somebody had seen her, but in reality nobody had seen her for two years," he said.

MISSING HARMONY MONTGOMERY'S FATHER ARRESTED IN NEW HAMPSHIRE

In general, but especially if children are out of school, everyday Americans should look out for warning signs, Walsh said.

"Children are our most precious commodity, and there are some evil people out there that harm kids," he said. "If you suspect any sort of foul play or bad behavior, absolutely report it. Children are so vulnerable."

Like Manchester Police Chief Allen Aldenberg, who called on the public to "do the right thing" and come forward with information about Harmony’s whereabouts last week, Walsh said people should go to bat for at-risk children.

"Do the right thing – call on behalf of that child," Walsh said. "Because at that point, that child has no voice. You need to be that voice."

Even though it’s been two years since Harmony’s last known sighting, Walsh said any details that witnesses may remember can potentially help investigators.

CLICK HERE TO GET THE FOX NEWS APP

"[A] member of the public may have that one little piece of information. However, they may think it's insignificant to the case, or it doesn't make sense, or it's stupid, and they don't want to call it out," he said. "But oftentimes that's exactly the key that unlocks the door to justice."

Manchester Police have set up a dedicated tip line, manned 24 hours a day by detectives, at 603-203-6060. Anyone with information is urged to call.