It entered the apartment through the air vents:

New Brunswick RCMP have launched a criminal investigation into the deaths of two young boys killed by a python that reportedly slithered through ventilation shafts after it escaped from a reptile store, though police say it's too early to determine whether charges will be laid.

Police confirmed that the store owner also resides in the upstairs apartment in Campbellton, N.B. where the two boys, aged five and seven, were found dead Monday morning. Reptile Ocean owner Jean-Claude Savoie was hosting the two boys, aged five and seven, for a sleepover with his own son.

Special thanks to Slog tipper Mary for giving me nightmares forever.