WHY teenage loner Kieron Smith turned child killer remains a mystery.

But at his trial at Liverpool Crown Court it was suggested that his background may point to why he brutally murdered and defiled the body of Lauren Pilkington-Smith - a girl he had happily played cricket with just a few hours before.

He suffers from Asperger's Syndrome, an autism-like disorder which can lead to eccentric behaviour, difficulties forming social relationships, problems with communicating with others and the development of strong narrow obsessional interests.

Smith left Lowton High School early, aged just 13, because he "didn't like the crowds and they made me feel anxious" - another symptom of Asperger's.

The education services worked with the family to try and find a solution but they failed and gave up when he reached 16. Instead of school, Smith spent most of his life leading a solitary existence, filling his days by watching TV, playing computer games and playing with the family dog, his canary, cockatiels and parrot.

Among his favourite programmes were Big Brother, sci-fi dramas, The Simpsons and the A-Team.

He had no friends his own age, but after school hours, Smith, at 6ft 1ins, would go out to play with children much younger than himself.

When he killed Lauren on July 7, Smith's mother step-father and sister were all on holiday in Turkey. His step-sister stayed at home to look after him.

Asperger's Syndrome may have caused his apparent odd behaviour and lifestyle, but according to medical experts it does not excuse or explain the motive for his crime.

A spokesman for the National Autistic Society said: "There is no established link between Asperger's Syndrome and offending."