13 Year Old Slashed Boy's Throat Because Of Playing Gears Of War 3?

In an argument about Gears of War 3, a 13 year old slashed another boy's throat

A thirteen year old boy from Clydebank, Scotland has been playing Gears of War 3.  Gears of War 3 is an Xbox 360 shooter game.  It is rated 17+ by ESRB.

Players use machine guns, shotguns, sniper rifles, and grenades to kill aliens and human soldiers in frenzied combat.  The game has a lot of blood and dismemberment.  A player can rip off an enemy's arm to use as a weapon.  Players can stomp on an enemy's head until it breaks apart.

Gears of War 3

The 13 year old met his 14 year old victim in 2011 while playing Gears of War 3 online.  The pair had disagreements online resulting to name-calling via the messaging system used in the game.

On the evening of April 14,2012, the victim and another boy were going to an house when they saw the accused.  The 13 year old boy grabbed the victim then struck him across the throat with a knife. The victim told paramedics a boy had ‘slit his throat in an argument about Xbox games’. He suffered a wound so deep it exposed his windpipe and required 20 staples following surgery.

The accused, who's a minor and can't be named, admitted to the assault.

A spokesman for Microsoft, which publishes Gears of War 3, said: ‘We have some of the most robust parental control systems to empower parents to decide how their children play and communicate. We have the greatest sympathy for the victim and his family.’

Is the game to blame, or the parents?