A teenager stabbed a 15-year-old girl to death and attempted to kill her father after she allegedly posted derogatory comments about another girl on Facebook, a Dutch court heard.
The boy, 15, identified as Jing Hua K, was jailed for a year and ordered to spend at least two years in a psychiatric facility to be 'treated for his problems'.
Judges awarded the maximum sentence possible in the Netherlands for a minor after the horrific murder in the eastern Dutch city of Arnhem.
Prosecutors told the court the murder happened on January 14, this year, after Joyce had a fight on the social networking site with a 16-year-old friend identified as Polly W. and her 17-year-old boyfriend Wesley C.
Wesley C then allegedly phoned and spoke to Jing Hua K. via Facebook to arrange the killing, and also allegedly discussed the possibility of killing Hau's entire family.
Jing Hua K went to Joyce's house, saying he had something to give her. When she came to the door he repeatedly stabbed her with a knife and then attacked her father, scarring his face for life, the court heard. The teenager died in hospital five days later.
'With the knife he deliberately stabbed her in the neck and face to take her life,' judges said. The girl was left 'in a lake of blood' and died in hospital five days later.
'The defendant did not know Winsie personally but he acted at the request of or on the instructions of another or others,' the verdict said.
Prosecutors said Polly's boyfriend Wesley C. had on December 9 last year asked Jing Hua K. 'to silence someone.'
During the case, witnesses testified that Jing Hua K was promised 150 euros ($183) if he carried out the murder.
In their sentencing, judges also said the troubled teen suffered from 'a serious behavioural disorder with psychopathic traits.'
Jing Hua's mother said her son had previously offered other teens money if they would play with him, according to the indictment.
Court spokesman Jaap Otten said that the details of the Facebook comments could not be discussed pending the trial of Polly W and Wesley C, for which no date has yet been set.
'The court is of the opinion the defendant deliberately killed' Joyce Hau, known as Winsie to her friends, as well as attempted to murder her father, judges said in a verdict posted online.