The large python that is believed to have strangled two young New Brunswick brothers while they slept was being held in the apartment where the boys were sleeping, not in the reptile store below as previously believed.

RCMP Sgt. Alain Tremblay confirmed during a news conference Tuesday afternoon that a criminal investigation has been launched into the incident in Campbellton.

He also said investigators are treating the Pleasant Street apartment and reptile store where the brothers were found as a crime scene.

Police said the 15-foot, 100-pound snake managed to escape its enclosure through a ventilation duct and entered the apartment's ventilation system.

It then fell through the ceiling into the living room where the brothers were sleeping on a mattress.

Tremblay said the bodies of the two boys were discovered by Jean-Claude Savoie, who lives in the apartment with his son, shortly after 6 a.m. Monday.

Dave Rose, the boys’ uncle, said they were spending the day with Savoie, who took them shopping and to a farm before they returned to his apartment for a sleepover.

"They had a super day,” said Rose. "That's the type of life they had and that's what we're going to try and remember."

Savoie told investigators he managed to trap the snake in a cage before alerting police. The snake was later euthanized by a veterinarian in Fredericton.

Autopsies on the bodies of the boys – who have been identified as Noah Barthe, 4, and Connor Barthe, 6 -- were performed in Saint John on Tuesday.

The RCMP said Monday they believe the snake strangled the boys, but Tremblay said Tuesday investigators are waiting for the results of an autopsy conducted Tuesday before commenting further.

"We can speculate, however, for the real cause of death we're going to have to wait for the pathologist's report," he said.

"As police officers in this type of investigation, we try not to focus on one thing. But at this point we believe the snake is involved."

Police have yet to say if any charges will be laid in the tragic deaths, which experts have described as extremely rare.

"I have 23 years of service, and I've never been involved in such a terrible story,” Tremblay said.

The RCMP have enlisted the help of a reptile expert from the Magnetic Hill Zoo in Moncton for their investigation.

Tremblay added that police will soon be meeting with Savoie, who owns the Reptile Ocean store.

He would not comment on whether Savoie had the right to hold the snake—which was identified as an African Rock Python – saying that the investigation is continuing.

"The investigator is still looking into whether he had all the rights to keep such (an) animal," Tremblay said. "There are a lot of things to look at. We're just at the first step of this investigation."

However, the New Brunswick government said no permit was issued for the python.

Steve Benteau, a spokesman for the provincial Natural Resources Department, said the province wasn't aware the snake was being kept at the apartment.

The department said the snake is generally only permitted in accredited zoos, unless there is a special permit.

CTV's Atlantic Bureau Chief Todd Battis said in the last 20 years, there haven't been any reported cases of snake strangulations in Canada.

Bry Loyst, curator of Ontario’s Indian River Reptile Zoo, told that the python may have mistaken the boys for food, explaining that snakes don’t intentionally attack humans.

The deaths have left the Campbellton community shaken and stunned.

“It’s a tragic, tragic thing,” said Terry Rose, great uncle of the boys. “Who would have thought something like this would happen around here? Especially in New Brunswick, something like that, but I don’t know what to say. Many weird things can happen in the world.”

"We're all overwhelmed here," Stephanie Bernatchez told The Canadian Press on Tuesday. "They could have been hit by a car, but a snake? That's not something people around here expect."

Bernatchez said she shares a mutual friend with the mother of the two victims, who are being remembered as fun-loving free spirits.

"They were two kids who were very well brought up," Bernatchez said. "Kind, polite -- they loved being together and playing together. They were sociable, played well with other kids."

Shawna MacEachern, a childhood friend of Mandy Trecartin, the mother of the two boys, said she was devoted to her children.

"She loved her babies. They meant everything to her," MacEachern said. "She was an awesome mother."

A fundraiser is being organized to help Trecartin with the cost of her sons’ funerals.

“She’s got some good people, good family that certainly are going to help her,” says Deputy Mayor Ian Comeau. “The community is going to rally.”

With files from and The Canadian Press