A teenager has been told he must spend a minimum of 17 years in detention and prison for the murder of a 16-year-old childcare student.
Evans strangled Karen and attempted to dismember her body
Colyn Evans, 18, strangled Karen Dewar, attacked her with a knife, pushed her body into a bin and set it on fire.
Evans had pleaded guilty to murdering Karen in Tayport, Fife, in January.
At the High Court in Edinburgh, Judge Lord Philip said Evans, originally from Aberdare, south Wales, must not be considered for parole for 17 years.
The judge sentenced the teenager on Friday after considering background reports.
Evans was also given a 10-year term for attempting to pervert the course of justice.
Lord Philip told him he had "robbed Karen's parents of the most important thing in their lives and shattered a peaceful community".
As Evans was sentenced, Karen's friends and family in the courtroom shouted abuse at him. One called out "animal" and "I hope you rot in hell Evans".
The Dewar family blamed social workers for "dumping" Evans in their village.
Fife Council placed Evans in a house in Tayport after he was released from a special needs school. He had committed six sexual offences between the age of 10 and 16, five of which related to shameless and indecent exposure.
The council asked the police to carry out a risk assessment on him but this was never done.
An internal review by the council and police reveals that Evans had been found to be at high risk of further sexual offending but it concluded there was no way Karen's murder could have been predicted.
The report calls for a consistent approach to the management of sex offenders who are not on the sex offenders register.
In May, the High Court in Edinburgh was told how Evans' flat was found splattered with blood and hair.
He had attacked Karen with a knife when he "lost the plot" following an argument.
Karen had befriended Evans after feeling sorry for him
Only-child Karen lived with her parents on the same street as Evans.
She was said to have befriended the teenager along with a group of friends who "felt sorry" for him.
Evans, who was 17 at the time, later told police that Karen had come to his house on 20 January and the pair had started arguing.
He later pushed her against a table, grabbed a bread knife and cut her hair and neck before attempting to strangle her.
He then dragged her downstairs and submerged her in a bath full of water.
A post mortem-examination revealed that Karen had died of strangulation.
Evans pleaded guilty to attempting to dismember Karen's body before putting it in a wheelie bin and setting light to it.
The court also heard how he had taken the wheelie bin into his hallway and stuffed her body into it, head first.
Her nearly naked remains were found after Karen's father had alerted police when she failed to return home.
Speaking outside court, Karen's father Frank, 44, who was accompanied by his wife Allison, said: "We feel that whatever the sentence given today would never be enough and it is Allison and I and our family that are going through a life sentence.
"We feel that if he gets out he will be dumped on someone else's street to do the same again and destroy another family."
Before moving to Tayport, Evans lived with his parents in Kennoway, Fife, where they had moved from Wales.
Local residents said the family was understood to have moved back to Wales.