CAMPBELLTON, N.B. -- A judge has told a jury it must decide whether a New Brunswick man showed "wanton and reckless disregard" for the safety of two boys killed when his python escaped during a sleepover.

In his instructions to jurors Wednesday, Judge Fred Ferguson told them to reach their verdict without "sympathy, prejudice or fear," to use common sense, and to consider the evidence against Jean-Claude Savoie with an open mind.

The jury is now deliberating a charge of criminal negligence causing death against Savoie, formerly of Campbellton, N.B., whose snake used a ventilation pipe to escape its enclosure in Savoie's apartment and asphyxiate Noah and Connor Barthe in August 2013.

In his closing arguments, defence lawyer Leslie Matchim said Savoie didn't cover the ventilation pipe above the enclosure because he simply didn't believe the large snake could possibly fit through it.

He said Savoie was convinced of that after the snake tried but failed to get through the same pipe weeks earlier.

But Crown prosecutor Pierre Roussel said failing to cover the opening showed disregard for others' safety.

Ferguson told jurors that the Crown must have proven "three essential ingredients" in order for them to convict:

- That Savoie, "as the only adult in his residence that night," had a duty to protect the brothers, and that he failed that duty.

- That he "showed wanton and reckless disregard for the lives and safety" of the boys.

- And that his failure to take "reasonably appropriate measures to care for or protect Connor and Noah Barthe" contributed significantly to their death.

"If Crown counsel fails to prove any one of these three essential ingredients beyond a reasonable doubt, you must find Jean-Claude Savoie not-guilty of criminal negligence causing death," the judge said.

Savoie was a longtime friend of the brothers' mother. His own son, who was sleeping in a different room that night, was unharmed.