The python that strangled two children in Canada had been kept in the pet store owner's apartment where the two brothers were sleeping and not with the other animals in the shop below, police said.
Royal Canadian Mounted Police Sergeant Alain Tremblay said the snake was housed in a large glass enclosure that reached the ceiling of the apartment. It escaped through a small hole in the ceiling connected to the ventilation system. He said the snake made its way through the ventilation system, the pipe collapsed and the snake fell.
Reptile expert Bry Loyst said the boys had been playing with other animals hours earlier, and he believes their scent might have attracted the snake.
Family spokesman Dave Rose, the boys' great-uncle, said the brothers had spent Monday at Savoie's family farm and played with llamas, goats, horses and dogs and cats before staying over at the apartment.
Investigators said they were waiting for the results of an autopsy on Noah Barthe, four, and his brother Connor Barthe, six, as well as a necropsy on the snake before commenting further on the cause of death.
BBC reported that police are now considering criminal charges.
Paul Goulet, founder and co-owner of Little Ray's Reptile Zoo in Ottawa, said snakes don't recognise humans as a source of food, but if the children smelled like animals, it could explain an attack.
"If a snake sees an animal moving, giving off heat and smells like a goat, what is it? It's a goat," Goulet said.
Loyst, curator of the Indian River Reptile Zoo in Ontario, said police told him it wasn't the first time that the python had escaped its enclosure. Police were not available to confirm whether that was true.
Steve Benteau, a spokesman for the provincial natural resources department, said no permit was issued for an African rock python and provincial authorities had not been aware it was being kept at the apartment. The department said the species was generally only permitted in accredited zoos unless there was a special permit.
The pet store owner, Jean-Claude Savoie, told the Global News television station that he didn't hear a sound and discovered the "horrific scene" when he went into his living room on Monday morning.
"I can't believe this is real," Savoie said.
He said the boys were the children of his best friend and were often at his apartment to visit his son. Savoie said the python, which he owned for at least 10 years, had been kept alone in its enclosure and was not handled by anyone else.
Additional reporting by Agence France-Presse