Two children on a sleepover at an apartment above an exotic pet store in Campbellton, N.B., were strangled to death by a python that apparently escaped from the shop.

RCMP said in a news release that its major crime unit was investigating after police were called to the apartment at 6:30 a.m. Monday. They found two boys, aged five and seven, dead.

"The boys had been sleeping over at the apartment of a friend, which is located above a reptile store," the Mounties said.

"The preliminary investigation has led police to believe that a large exotic snake had escaped its enclosure at the store sometime overnight, and got into the ventilation system, then into the upstairs apartment. It's believed the two boys were strangled by the snake."

The snake was captured and was in the RCMP's possession.

Autopsies were scheduled to be performed on Tuesday.

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The snake apparently escaped from Reptile Ocean Inc., whose Facebook page was hit with negative comments as soon as the news broke.

The news created stunned disbelief on Twitter.

What?? @CBCAlerts: #RCMP say escaped python kills 2 boys, 5 and 7, in N.B. #Python slithers into apartment above Campbellton pet shop — rick westhead (@rwesthead) August 5, 2013

"This is a tragedy," Campbellton Deputy Mayor Ian Comeau told CBC News. "The city is in shock."

CBC News reported that in 2009, the New Brunswick government relaxed restrictions on lizards and other exotic pets, including allowing the sale of non-poisonous snakes up to three metres long.

A provincial wildlife biologist said at the time the change was made after lobbying from pet-store owners who argued New Brunswick regulations were stricter than other jurisdictions, CBC News said.

Three years ago, Florida woman Jaren Here and her boyfriend, Charles Darnell, were sentenced to 12 years in prison after their pet Burmese python escaped from its enclosure and strangled Hare's two-year-old daughter in 2009.

ABC News reported the couple was convicted of third-degree murder, manslaughter and child neglect. The court heard the tank holding the 150-pound snake was covered only by a quilt.

[ Related: Winnipeg man finds 5-foot python in a dumpster ]

And in 2010, an Omaha, Neb., man died after his pet boa constrictor strangled him while he was showing it to a friend, the Omaha Herald Sun reported. Paramedics called to Cory Byrne's apartment were able to pry the nine-foot snake from around his neck and shoulders but he died later in hospital.

The Globe and Mail reports Reptile Ocean has been in business for 16 years.

The Globe said the store received a good review in a 1996 report by Zoocheck Canada Inc. and the World Society for the Protection of Animals. Veterinarian Dr. John Gripper reported the reptiles in the store appeared in good health and the water in their tanks was clean.

However, the Globe also said someone had started an online petition to close the store, complaining about the condition of some animals and the humidity in the store.