Neighbors of Christopher Miller on Long Island described him as a friendly and kind person who interacted well with children. They find it hard to believe that he could be capable of murdering his father, a police officer, in such a brutal manner.

Fellow residents of quiet, leafy Bruno Lane in Dix Hills said they were “stunned” that the 43-year-old has been charged with the vicious slaying of former Suffolk County Police Department Detective John “Jack” Miller — as he showed no sign of mental illness and was well liked by all.

“He was a pillar of the community,” neighbor Joyce Gimeli said of John. “He was the nicest man, I’ve lived here for 42 years and never had a bad thing to say about him.”

She and other neighbors told The Post they heard no gunshots on the morning of the slaying, but they knew something was wrong when the block filled with police cars.

Neighbors also described Christopher, who plead not guilty by reason of insanity, as never seeming “off” or mentally ill.”

“He was terrific. I don’t want it to not be said what a nice kid he was,” Gimeli said about Chris, calling him “one of the pack,” growing up alongside her daughter.

However, she mentioned that as of recently, a friend of her daughter had expressed that Christopher may be “depressed,” and had tried reaching out to him to offer support but was ultimately rejected.

“That boy, Chris, was just an adorable child,” Gimeli told The Post. “He must’ve gone mentally ill recently. What makes somebody that was so wonderful snap like that?”

Neighbors mentioned that Christopher lost his mother about five years ago and was now going through a rough divorce, and back living with his father — but said everything seemed normal on the outside.

“I saw the son two weeks ago out here playing basketball with his kids,” said Antoinette Tufano, pointing to a neighbor’s hoop in front of the driveway.

“I waved at him, he waved back, everything seemed fine,” she told The Post. “I guess you never know how people are behind closed doors.”

After his arrest, Christopher chillingly confessed to his father’s murder — telling detectives he walked up to his father’s wounded body and blasted him in the head to “finish him off,” prosecutors revealed Thursday.

“I would hate for him to be painted like a monster because I don’t think that’s it,” said Gimeli. “He snapped in some way and did a very horrible thing.”

Neighbors say they are now left searching for answers and picking up the pieces of this now broken community.

Christopher allegedly blasted his father multiple times with a shotgun during an explosive argument inside their Dix Hills house around 7:25 a.m., according to police.

The murder took place when Christopher came home after getting released from a local hospital following a Monday car crash, according to News 12 Long Island.

His father hadn’t heard from him and reported him missing a day before he was killed.

Police believe a heated argument ensued, leading to Christopher murdering his father.

After the deadly shooting, Christopher ran and hid in a neighbors shed, leading the spooked homeowner to call 911.

Responding officers recognized him because of his father and decided to take him back to his home.

Upon entering, the cops escorting Christopher found the father dead in a pool of blood and arrested him on the spot.