The maternal grandmother of a toddler who died after being left in a scorching car last week has been charged with criminal negligence causing death and failing to provide the necessaries of life.

Maximus Huyskens was in the care of Leslie MacDonald, 51, when he died of heat stroke on June 26.

Maximus would have turned 2 on July 29.

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A handful of similar cases occur every year in Canada, and each one is treated differently. Depending on whether the child survives or dies, police have laid a variety of charges, from child abandonment to manslaughter.

Police said an autopsy shows the boy died of heat stroke after being left in the car outside a home in Milton, Ont., for "an extended period of time" as temperatures climbed to 31 C. The boy's grandmother is deaf, but police have not said whether that was a factor in the incident. The criminal negligence charge could have a maximum sentence of life in jail.

According to the Criminal Code of Canada, a person is criminally negligent when they "show wanton or reckless disregard for the lives or safety of other persons." The charges in this case were laid on Friday after more than a week of investigation. Police spoke with family and witnesses to piece together what occurred, said Sergeant Dave Cross, media relations officer for the Halton Regional Police Service.

Sgt. Cross could not comment on the case specifically, but said police initially treat any death as suspicious and determine if it is due to natural causes, a homicide, a suicide, an accident or undetermined causes. In the case of criminal negligence, the death is technically ruled a homicide, he said.

"If you look at the charges, it's not homicide in the sense that the person was not charged with murder, but it's classified as such," Sgt. Cross explained.

Earlier this week, a three-year-old girl in Edmonton was found dead in a hot car. No criminal charges were laid in that case because police said the toddler was not left by a parent or guardian in the vehicle, which was unlocked.

Clair Seyler, a spokeswoman for the Edmonton Police Service, said officers work with Crown attorneys to determine charges.

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"It would have to come up in an investigation to determine if it was an accident that couldn't be prevented or if it should have been prevented," Ms. Seyler said. "It's beyond forgetfulness when a life is involved."

In Canada, charges against parents who leave their children unattended in cars include everything from abuse and child abandonment to manslaughter. In nearly all cases, child welfare authorities are called, according to Caroline Newton, the director of communications for the Ontario Association of Children's Aid Societies.

"I can't think of a circumstance where we wouldn't want to go and see what's going on," Ms. Newton said. At minimum, a conversation will take place to ensure it does not happen again, but in an extreme case, a child could be removed from the home, she said.

Still, some argue the death of a child is punishment enough. Often, even when charges are laid, the Crown will have sympathy for the bereaved family.

In 2004, Crown prosecutors dropped manslaughter charges against a Montreal father in the death of his 23-month-old daughter. She died of heat stroke after he forgot to drop her off at daycare and left her in the back seat of their car on a hot July day.

Prosecutor Manon Ouimet told reporters at that time it was a mistake any reasonable person could make.

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That's the stand Lyn Balfour takes. The U.S. mother from Virginia faced a charge of second-degree murder in 2007 after she accidentally left her nine-month-old son, Bryce, in a hot car and he died of heat stroke. She was acquitted by a jury and has dedicated herself to educating other parents about the deadly mistake, which she says anyone can make.

"People don't understand it could happen to you. You could never imagine forgetting your child," Ms. Balfour said in a phone interview on Friday. She said when people assume they could never make the same mistake, they ignore precautions. "Until people understand it's an accident, it's going to continue to happen. I never want another parent to feel how I feel every day."