08/10/2013 06:05 EDT | Updated 10/10/2013 05:12 EDT

Funeral today for New Brunswick brothers killed by python

St. Thomas Aquinas Church in Campbellton, N.B., is expected to be full for this afternoon's funeral for two young boys who were killed by a large snake as they slept.

Noah Barthe, 4, and his brother Connor, 6, were killed last weekend by a 45-kilogram African rock python, which had escaped from its glass enclosure in an apartment above an exotic pet store, Reptile Ocean.

It's believed the python made its way through the top of the enclosure and into a ventilation system before falling through the ceiling and into the living room of the apartment. The animal was 4.3 metres long and weighed about 45 kilograms.

They were there for a sleepover with the son of the shop owner, Jean-Claude Savoie. That boy had been sleeping in another room and was unharmed.

Ian Comeau, Campbellton's deputy mayor, said Noah and Connor will be buried in the same casket and today's service will celebrate their short lives.

During a stop yesterday in Miramichi, N.B., Prime Minister Harper called it a "strange and terrible event," adding everyone feels "very deeply" for the boys' family.

A preliminary autopsy found the boys died of asphyxiation and a criminal investigation has been launched.

Steven Benteau, a spokesman for the Department of Natural Resources, told CBC News on Tuesday, a day after the boys' bodies were discovered, that African rock pythons are not permitted under the province's Exotic Wildlife Regulation.

The coroner's office in New Brunswick has said there will be no decision on whether to have an inquest until after legal proceedings are complete.