York Regional Police, the coroner and provincial officials are investigating the death of a nine-month-old child at an unlicensed home daycare in Markham, north of Toronto.
Police say they were called to the daycare late Wednesday afternoon for a report of a girl who was not breathing.
The infant was transported to hospital where efforts to revive her were unsuccessful.
Investigators say an autopsy conducted Thursday found no anatomical cause of death.
Anyone with information is asked to contact the York Regional Police homicide unit.
Ontario's Education Ministry says a preliminary review has found no complaints related to the daycare, and is conducting an investigation under the Day Nurseries Act.
"My heart goes out to the family and loved ones of the child at this devastating and unimaginable time," Education Minister Liz Sandals said in a release.
The ministry is being sued by the family of a two-year-old girl who died last summer in another unlicensed daycare in York Region.
Eva Ravikovich's parents launched a $3.5-million lawsuit against the ministry and the owners and operators of the daycare in Vaughan, Ont.
Their statement of claim does not reveal what the family believes happened inside the daycare that led to their daughter's death, but alludes to an "incident."
Ombudsman Andre Marin has launched an investigation into whether the government is doing enough to protect children in unlicensed daycares.