[Mana]

Saying it's because of videogames is really stupid. Not all guys that play videogames shoot their friends... and there are also othe influences in life, like movies, cartoons, books and so on, not only videogames.
If the person who acts in this way is not a balanced person doesn't really matters: he will do something silly and unpredictable like it happened in this case, videogames or not.