Two men have been jailed for the frenzied stabbing of a teenage girl, who they left to choke to death on her own blood in a Lancashire park.
Louise Evans, 18, who had Asperger's syndrome, was stabbed so hard in the attack in Burnley that the knife broke in two, Preston Crown Court heard.
Anthony Wood, 21, from Burnley, was found guilty of murder and jailed for at least 22 years and 183 days.
Matthew Maw, 18, admitted murder and must serve 18 years and 63 days.
Their teenage victim suffered 39 head and neck injuries in the assault in Towneley Park in July 2009.
Her killers, who had befriended her at a homeless hostel they all shared in the town, led her to a secluded spot by a disused bandstand and "brutally" attacked her, the court heard.
Ms Evans' throat was slashed and she was repeatedly bludgeoned with a branch.
Louise Evans was stabbed and beaten
On sentencing, Judge Anthony Russell QC told the court that Maw, also from Burnley, had inflicted most of the physical violence but Wood had persuaded him to do his "dirty work" for him.
He told the them: "You were prepared to go beyond all basic moral boundaries and act in a fashion referred to as feral violence - completely wild behaviour inflicted on a vulnerable victim for no reason at all.
"The sanctity of human life appears to mean nothing to you. This was a savage attack, carried out relentlessly.
"Louise must have suffered terribly because she did not die instantaneously.
"The only word that even begins to describe your conduct is 'wicked'."
They had been part of a group of youngsters who had been on a drinking session the evening before the attack.
Matthew Maw admitted murder
Ms Evans, from Haslingden, been living in the hostel because she wanted to be independent, her adopted parents said in a statement read to the court.
She had complex needs but was "special" and "loved dearly," Louise and Jeff Evans said. "We are lost and empty and in disbelief that somebody could do this.
"There is a void in our lives that will never be filled."
Speaking after the case, Det Insp Paul Broxson, from Lancashire Police, said his thoughts were with Ms Evans' family, who had lost their daughter in "such tragic circumstances." He said: "I am very pleased with the sentence which reflects the horrific and sustained nature of this attack.
"As for Maw and Wood, this was a particularly brutal and cowardly assault, planned and carried out together, and they fully deserve their sentence."