A teenage babysitter who battered a toddler to death while her mother popped out to the shops was found guilty of murder today.
The 15-year-old boy inflicted 68 injuries on two-year-old Demi Leigh Mahon because he was fed-up with her behaviour, the jury heard at Manchester Crown Court.
The boy, who admitted manslaughter, took her to a park before attacking her at a house in Salford, Greater Manchester, on July 15 last year.
The attack on Demi Leigh was so ferocious - she was punched repeatedly in the face - that she was left brain-damaged.
Pathologist Dr Naomi Carter said part of her scalp was also sheared off, most likely as a result of it coming into contact with a hard surface.
Demi Leigh had what doctors believe were bite marks on her right arm and back, and her ears were either pulled, pinched or kicked.
Dr Carter told the jury it was neither "reasonable or credible" that the vast majority of the injuries were sustained accidentally.
Demi Leigh was left with the boy, who cannot be named for legal reasons, by her mother Ann Marie McDonald.
She told the jury she went out for about 90 minutes to collect a child benefit cheque.
Ms McDonald had left her daughter with the boy on several occasions.
She returned to find the boy standing outside the house. Ms McDonald said he told her: "I picked her up - I might have hurt her - and she fell in the park."
Ms McDonald, known as Sindy, rushed inside and found her daughter lying on a bed. Sobbing, she told the jury: "Her face was bruised. I tried to pick her up and her head flopped back. She couldn't breathe properly.
"I screamed 'Why haven't you rung an ambulance?'. He said 'I never done nothing, I've not done nothing'."
Demi-Leigh was taken to hospital, where she was met by five doctors. Her parents were at her bedside when her life support machine was switched off two days later.
Psychiatrist Dr Cesar Lengua said the boy made the following admission to a health worker: "I'm not proud of what I've done and everyone will think I'm a monster but nobody can ever punish me as much as I'll punish myself."
Dr Lengua, who was called by the defence, said the boy suffered from an unsocialised conduct disorder and had a "below normal" IQ.
He said it was clear there were "disharmonious relationships between the parental figures in this boy's life" and family dynamics were crucial to understanding the development of his conduct disorder.
The jury heard that the boy has never explained his attack on Demi Leigh but has alluded to the fact he was angry with her behaviour.