Where is the glitch?

A beautiful 19yr old upper-class girl (half Swedish and half Sri Lankan) was brutally murdered inside their luxury apartment complex in Colombo last month. Her name is Yvonne Johansson and was a Fashion Design student who had just come back home after studying for 2years in the US. She along with her 16year old sister(Caroline) and Caroline's 21year old boyfriend (Sharmantha - apparently ex-boyfriend of Yvonne) had gone out clubbing on the night of June 30th. And later, Caroline and Sharmantha have had some silly argument and they had come home early (to the girl's apartment at around 2am), leaving Yvonne in the night club. Yvonne had later driven home (around 3am) and Sharmantha had been waiting for Yvonne near the lift on the 23rd floor. Then they had some sort of argument (God knows what) and then she had chased him down the steps down to the 19th floor. That's where the murder took place. Her head was brutally banged against the walls and the face was wrecked being repeatedly smashed against the steps. She was strangled using her own jeans and left to bleed and die. Apparently she had no face and her sister could not identify Yvonne for the Police, the next morning when they found her body. How tragic and cruel is that?

Part of the story here:

http://www.dailynews.lk/2005/07/06/news12.htm

Yvonne's photo in a Swedish newspaper here:

http://www.dagbladet.no/nyheter/2005/07/04/436426.html

Note that both Yvonne and Sharmantha come from extremely wealthy and upper-class families in Sri Lanka and have known each others' families since childhood. They both went to Colombo International School - CIS (one of the prestigious International schools in Sri Lanka). I find this story just too shocking-gave me the goosebumps! What a waste of a young life and how many more Sharmanthas are out there? What a total loser and a pathetic moron he is. Some people have everything they want in life and then they invite unwanted things into their lives, why? Who could be blamed here? Some blame the International school system where Western culture is encouraged. I find it ridiculous to blame an entire school or and entire culture because of one rotten apple! Some blame the parents for bringing up children with too much freedom. I find that ridiculos too! I mean both were adults (19 and 21) and how can parents stop them from doing what they want at that age? After all clubbing isn't so much of a crime, is it? I think the entire blame should be on the guy...he is the doer of the crime and that's it. No matter how much rage you experience during an argument, no civilised guy would commit such a low and gruesome act. What say?