Hamilton police have charged a 39-year-old woman with manslaughter in the death of her four-year-old son.
Police say the boy's death in September 2017 initially did not seem suspicious as he had been born with a number of medical issues and undergone several surgeries.
But three months later, police say toxicology results indicated the child had died as a result of a lethal dose of unspecified drugs.
Police say in February 2018 they notified the boy's parents that they were suspects in their son's death, at which point they stopped co-operating with the investigation.
As the probe continued, police say they learned that the boy's mother had moved to Newfoundland and given birth to another child, who is now in protective custody.
Police say they arrested the mother in Newfoundland earlier this week and brought her back to Ontario to face the manslaughter charge.