A mother who carried her "unresponsive" two-year-old son into a police station yesterday morning has been arrested on suspicion of his murder.
The boy was taken by ambulance from Peterlee police station in County Durham to Sunderland Royal Hospital, where he was confirmed dead shortly after arrival.
His 39-year-old mother was then arrested and held at the same police station, officers said, after injuries were found on the boy's body.
The woman, from the Castle Eden area, is 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.
The woman reportedly walked into the building's reception area between 7.30am and 8am carrying her son in her arms.
"The child was not responsive and an ambulance was immediately called for," a police spokesman said. "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."
A post-mortem examination was due to take place last night to establish the cause of death. Durham Police said the child would not be named at this stage.
"A team of officers is working on the case and an incident room has been set up," the spokesman added.