A report into a teenager's murder at a Lincolnshire school has said his death could not have been prevented.
Luke Walmsley was stabbed in the heart at school
Luke Walmsley, 14, was stabbed by fellow pupil, Alan Pennell, now 16, at Birkbeck School in North Somercotes.
The independent report for the Lincs Area Child Protection Committee found that a "culture of fighting" among Luke's peers led to his death.
But the report also labelled it "an extraordinary event" which could not have been foreseen or prevented.
Pennell, of Grainthorpe, Lincolnshire, will serve a minimum of 12 years after being convicted of murder.
The Serious Case Review also found that the 16-year-old killer's past history of unruly behaviour and self-harming was not properly recorded and therefore the event could not have been predicted.
The panel believes that the interaction between these two boys and their associates was not bullying
Paul Tudor, report author
Most computers will open PDF documents automatically, but you may need to download Adobe Acrobat Reader
It rejected the suggestion that Pennell, who had been suspended from school twice before, had been allowed to act due to a "catalogue of errors".
There were, it said, "no significant shortcomings" in the agencies involved and disciplinary procedures put in place by the school's head were suitable.
Author Paul Tudor stated: "The fatal incident was a premeditated single act within a school setting. It was an extraordinary event with the most tragic outcome.
"The panel believes that the interaction between these two boys and their associates was not bullying.
"The interactions between Alan and Luke and various other male young people represented altercations and a culture of fighting and some violence.
I don't think he (Pennell) should have even been in the school. If he hadn't been in school he would not have been able to kill Luke
"For Alan... these dynamics became unmanageable and were tragically played out in school on November 4, 2003."
Luke's mother, Jayne, said she was disappointed the report did not accept that Luke was being bullied.
She also felt Pennell had been given too many chances.
"I don't think he should have even been in the school. If he hadn't been in school he would not have been able to kill Luke," she said.
Luke's parents have called for greater powers to tackle disruptive pupils and greater punishments for youngsters caught carrying knives.
The independent inquiry team, which was set up in September to examine the events surrounding Luke's death, has interviewed officials from the education authority, social services and the NHS.