A 16-year-old from Cornwall who swung a baby boy against a fireplace "like a baseball bat" has been found guilty of manslaughter.
Christopher Phillips was 15 at the time of the offence
Christopher Phillips of Saltash had pleaded not guilty to murdering nine-month-old Harley Rogers at Buller Park in December 2002.
He was convicted of manslaughter, on the grounds that he did not intend to cause the child serious harm.
His case was adjourned for reports, but he was warned he faced prison.
Christopher Phillips did not give evidence before the jury, but told the police in an interview "I never harmed that baby".
His brother Michael Phillips, who was normally known as Craig, of Wilton Terrace in Pelynt, denied causing the baby actual bodily harm.
The court heard how Michael Phillips punched the baby - the child of his partner Laura Shenton and another man - in the face, drawing blood.
He also denied perverting the course of justice by threatening Blake Nettleinghame, a key witness.
He was found guilty of both charges.
During the trial, Mr Nettleinghame told the jury the impact of the back of the child's head when he was "swung like a baseball bat or cricket bat" against the fireplace made a noise "like a brick on concrete".
Mr Nettleinghame said in the following days Harley was "lifeless and drowsy".
Sarah Munro, prosecuting, said the child was showing signs of having suffered a serious head injury and was "clearly dying".
The court heard how Michael Phillips punched Harley in the face
A doctor diagnosed a chest infection and Miss Munro said the baby's mother had no idea what had happened to her child and bruises were concealed by hair.
The child was taken to hospital where gastroenteritis was diagnosed and he was allowed home with instructions to the mother to monitor him.
By 1100 the next day, 21 December 2002, he was dead.
The fatal injury was haemorrhage over the brain, which must have occurred about 36 hours before he died said Miss Munro.
Harley's mother said in a statement after the case: "The death of my nine-month-old son is a tragedy which has devastated me.
"Nothing will bring back my son or make up for his loss."