A mother who carried her "unresponsive" two-year-old into a police station has been arrested on suspicion of his murder.
The boy was taken by ambulance from Peterlee police station, County Durham, to Sunderland Royal Hospital, where he was confirmed dead shortly after arrival.
Due to injuries found on his body, the mother, 39, was arrested and held at Peterlee, Durham Police said.
The woman, from the Castle Eden area, was believed to have parked a Skoda Octavia outside the magistrates' courts which adjoin the police station.
The vehicle has been taken away for forensic analysis.
She walked into the modern police station's reception area between 7.30am and 8am on Monday carrying her son in her arms, Durham Police said.
A spokesman said: "The child was not responsive and an ambulance was immediately called for.
"He was then rushed to Sunderland Royal Hospital where, despite the efforts of doctors, he was confirmed dead shortly after arrival.
"Due to injuries on the child's body, the 39-year-old woman was arrested on suspicion of the boy's murder, and she is now in custody at Peterlee police station."