Police in eastern Canada have launched a criminal investigation after a python apparently escaped from a pet shop and killed two children by asphyxiating them in their sleep.
The two boys - named locally as Noah Barthe, five, and his brother Connor, seven - were at a sleepover at their best friend's flat in the town of Campbellton when it is believed they were attacked by the snake.
It is understood the animal had escaped from the Reptile Ocean pet shop, which specialises in exotic pets and is run by family friend Jean-Claude Savoie, located on the ground floor of the building.
The boys were sleeping in the living room of the residence on Pleasant Street when they were reportedly attacked by the snake early on Monday morning. Police were called to the scene at 6.30am local time.
Corporal Alain Tremblay from the Royal Canadian Mounted Police (RCMP) told Canadian news station CBC News that officers were in the first stage of a criminal investigation.
He said: "I can tell you it's a criminal investigation right now to determine if any criminal act is responsible for the death of the two boys."
Cpl Tremblay confirmed that the snake involved is an African rock python, as long as 4.5 metres and weighing about 45kg. The animals are non-venomous and would usually kill by constricting victims.
Police have suggested the python entered the upstairs apartment via the two-storey building's ventilation system.
The RCMP said in a statement: "The preliminary investigation has led police to believe that a large exotic snake had escaped its enclosure at the store.
"(It) got into the ventilation system, then into the upstairs apartment. It's believed the two boys were strangled by the snake."
The boys' mother, Mandy Trecartin, lives close to the Reptile Ocean store. She is a good friend of the shop owner and regularly let her sons stay over there.
A former shop employee is reported to have called Ms Trecartin as soon as he heard about the tragedy to find out what happened.
Tim Thomas told Canada's National Post: "She told me straight up, it was her two children that died; I didn't know what to say, I was in shock."
Mr Savoie, who described the dead brothers as "like an extended family", told Global News that he found a "horrific scene" when he checked on the boys at about 6am.
"I thought they were sleeping and I've seen the hole in the ceiling, (and) everything has fallen. I turn the lights on and I've seen this horrific scene," Mr Savoie said.
He added: "The snake was gone but I found the snake ... it went through the ceiling and was sleeping in the living room.
"I have so many mixed emotions right now. I can't believe this is real."
The python, which he had owned for 10 years, has been recaptured.
The local community expressed shock at what had happened. One neighbour said: "We could not believe that something like this could happen, but it has happened."
But another Campbellton resident was less sympathetic. She said: "The fact that you have an apartment with animals like that below, the risk is always there."
Experts said attacks on humans by exotic snakes are extremely rare and, according to local officials, the reptile owner was fully licenced.
Exotic snake seller Alexandre Tremblay suggested the snake must have been "way under-fed and badly housed".
"For a snake to be able to get out of that size it just has to be really hungry and not in good conditions. Because usually snakes are very easy-going ... it's rare that snakes get out," he told Sky News.
Lisa Janes, co-owner of Little Ray's Reptile Zoo, a zoo and education programme in Ontario, told CBC News that snakes do not usually see humans as food, pointing out that more people are killed by dogs than by snakes.
According to a report in the the Toronto Sun, snake expert Michel Leblanc is baffled over how the snake was able to kill both boys.
"It is rather odd ... because usually the snakes feed on rabbits, for example.
"Generally, it will only attack something he can swallow. It will not kill for nothing," he said.
Reptile Ocean's Facebook page was flooded with criticism when news of the deaths spread and has now been shut down, the National Post reported. An unknown administrator earlier replied to the angry comments saying it had been "a terrible accident without a meaning".
"There is nobody to blame. The snake broke out of its enclosure. The enclosure was locked. There was no negligence. This is a terrible accident," the message posted on Monday afternoon read.
An online petition calling for the shop, which reportedly has three employees, to be shut down had been started prior to the deaths. It has been open for almost 17 years.
Post-mortem examinations on the two boys' bodies are due to be carried out today.