Hua was murdered when Jing Hua K, 14, was offered 150 euros to kill Joyce Hua (seemingly no relation).

The girl about whom the comments were made is known only as "Polly" - she cannot be identified because of her age. She and Joyce had a public spat on Facebook. Polly's boyfriend Wesley C, 18, asked - say prosecutors - Jing Hua K to "silence someone."

He went to Joyce Hua's home, said he had something to give her and then, when she opened the door, attacked both her and her father with a knife. The girl died five days later from injuries from multiple stab wounds, her father suffered scarring to his face.

Both Polly and Wesley C have been jailed for two years then sent for two years' psychiatric care, one of which has been suspended.

The growth of social media in the Netherlands is remarkable with government figures showing a market penetration of more than 90%.

Facebook happens to be, currently, one of the best known (these things go up and down - just ask MySpace and Friendster ) but there are many. The lack of self-control by posters is already causing problems in a wide range of employment and law enforcement environments.

But this case is a new low for reaction to online comments.

And it's very difficult to see how parents, employers or anyone else can control the posting of comments and the reaction they may engender, especially in the potentially unstable.