The jury heard he fantasised about killing his headteacher and parents
A British boy who idolised the Yorkshire Ripper has been convicted of murdering two strangers in frenzied attacks.
James Fairweather, who was 15 at the time, stabbed James Attfield (33) 102 times in a park in Colchester, Essex, in March 2014.
Three months later he knifed Saudi student Nahid Almanea (31) as she walked along a nature trail in the town.
After the verdict a senior police commissioner said easy exposure to internet pornography and violence were partly to blame for the tragedy.
The 17-year-old admitted manslaughter, claiming he believed he was possessed by the devil and heard voices that compelled him to kill.
He denied murder on the grounds of diminished responsibility but was convicted by a jury at Guildford Crown Court.
A ban on reporting the boy's identity has now been lifted.
Fairweather showed no reaction as the jury delivered its unanimous verdicts after deliberating for eight hours and 33 minutes.
Mr Justice Robin Spencer QC warned he faced a lengthy prison sentence, adding that the starting point would be 12 years.
He will be sentenced at the Old Bailey on Friday April 29th.
The court was told how Fairweather went from being a well behaved child to a teenager obsessed with sexual violence and serial killers.
He was hunting a third victim when he was caught by police.
The teenager was "turned on" by serial killers and researched Ian Huntley, Myra Hindley and Yorkshire Ripper Peter Sutcliffe.
He had a picture of Sutcliffe on his phone.
His favourite serial killer was American Ted Bundy, who sexually assaulted, murdered and decapitated his victims, the court heard.
He wanted to emulate the serial killers he idolised and fantasised about killing his headteacher and parents, the jury was told.
The young killer had played violent computer games 'Call Of Duty' and 'Grand Theft Auto' since he was 13-years-old.
He had a stash of horror films including 'Wrong Turn: The Carnage Collection', a DVD about Sutcliffe and a book called 'The World's Worst Crimes'.
After he killed, he obsessively looked up press coverage of the murders on the internet, his trial was told.
He spent his days thinking about "killing, raping and watching pornography", the jury of five men and seven women were told.
The double murder sparked a massive police hunt in Colchester, and the teenager did not attack again for another year.
He was arrested on May 26th last year while wearing gloves, armed with a lock knife.
He was on the prowl for his third victim by the Salary Brook nature trail where he had already killed.
After the verdict, Essex Police and Crime Commissioner Nick Alston said youth exposure to internet porn and violence were partly to blame.
He said: "This case highlights the need for all of us to be prepared to talk about not only the harm being perpetrated by our young people, but also the likelihood that harm is being caused to them by repeated exposure to extreme violence and pornography, both of which are readily available on the internet and both of which we have heard cited in this case".
Fairweather, who has been diagnosed with autism, admitted the killings.
In police interviews he told detectives he heard voices, adding: "They said we need another sacrifice and I was going to get my third victim but there was no-one about".
His defence lawyers argued that he had full-blown psychosis and did not fully understand what he was doing.
But this was dismissed by prosecutor Philip Bennetts QC, who said the youth "understood his conduct at the time".
He "was able to form a reasonable judgment", the court was told.
Mr Bennetts said Fairweather made preparations for killing and "took steps to conceal afterwards" by throwing his weapon into a river.
The court heard that Fairweather lied about hearing voices and having hallucinations to try to get off the murder charges.
Psychiatrist Dr Philip Joseph said the teenager's description of hallucinations were "cliched" and "unconvincing".
He added: "It seems more like something you might see in a horror film".