A young mother and her partner have been arrested on suspicion of murdering her four-year-old son.
The child died of a head wound after being found unconscious at his home in the Holbrooks area of Coventry on Saturday, police said.
A West Midlands force spokesman said the man, 32, and woman, 26, remain in custody today after being arrested on Monday.
The boy was found not breathing in the early hours by officers.
A forensic post-mortem examination which took place yesterday revealed that he died as a result of a head injury.
A police statement said the suspects "remain in custody this afternoon, where they continue to help police with their inquiries.
"Detectives from the force's public protection unit are working closely with the local authority as the investigation progresses and support is being offered to the boy's family."
The victim is likely to be named later after next of kin have been informed.