The one-year-old boy became unresponsive at a Sebastopol home in Ballarat around midday on November 4, police were told.
He was taken to hospital by his mother and her partner, but sadly died in a Melbourne hospital two days later.
Detectives yesterday arrested a 26-year-old woman and an 18-year-old man.
They were interviewed and released pending further enquiries.
Police are yet to determine the exact circumstances leading up to the boy’s death.
