Demi Leigh Mahon died from head injuries
A 15-year-old babysitter accused of murdering a two-year-old girl in his care said he was "not proud" of what he did, a court has heard.
The teenager admits unlawfully killing Demi Leigh Mahon but denies murder on the grounds of diminished responsibility.
She was found with 68 injuries on her body in Salford in July last year.
Manchester Crown Court heard evidence from the boy's psychiatrist and a pathologist in the latest session.
Psychiatrist Dr Cesar Lengua told the court that the boy, who cannot be named because of his age, told 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 told the jury the boy's poor ability to think and regulate his emotions and what he called his "poor moral development" had more influence over his actions than his poor intellectual ability.
Dr Lengua said: "He has a poor understanding of other people's emotions and other people's functions."
He added the boy had difficulties in explaining his attack on Demi Leigh.
He said: "He alluded to the fact that he was angry... to the fact that he had told her to be quiet."
The jury also heard that the boy was "fed up" because Demi Leigh was crying and would not do as she was told, but has never explained his actions.
The trial continues.