Were the video games to blame for killings and violence

No, not if used correctly. If a 3 year old plays GTA 5, that could have some affects on his psychological well being, whilst a 15 year old playing GTA 5 would be much more mature about it. That's why ratings exist. So in a whole... Video games may be blamed for some elements of violence in human but the blame should be rested with the parent who ignored the rating of the game.