A man has admitted killing his four-month-old son in an "act of deliberate and unlawful violence".
Sam Gildea, 30, of Partington, Greater Manchester, pleaded guilty on Wednesday to the manslaughter of Alfie Gildea.
Emergency services were called by the boy's mother after she returned home to find Alfie unconscious on the morning of September 12.
The youngster was taken to hospital with significant head injuries but died two days later.
Gildea was due to stand trial at Manchester Minshull Street Crown Court accused of murder but his guilty plea to an alternative count of manslaughter was accepted by the Crown.
Andrew Thomas QC, prosecuting, said the plea had been tendered on the basis that the defendant admits he caused Alfie's death with an "act of deliberate and unlawful violence which involved rigorous and violent shaking".
Gildea also pleaded guilty to a charge of controlling or coercive behaviour towards Alfie's mother.
Sentencing will not take before Friday at the earliest as the issue of the defendant's dangerousness is assessed.
The court heard that Gildea had a history of involvement with mental health services.