Do violent video games cause behavioural problems

No. In my view, videos games have a restricted age limit for a reason. If a child plays a game should as GTA, they may act like the character on GTA but why as a child been playing a 18 restricted game.
There should however been no behavioural difference if playing a violent video game because a video game is for only entertainment purpose's.

There was an article about a young boy killing another boy. Police searched his room and found a game called man hunt. The police suspected that the game has something to do with the killing. This boy was only young and has a video game which stated that 18's + should play this game. Why did he have it in the first place and why would police suspect that the game was to blame. The game got banned for a while but was released again after several weeks.

After playing it myself, the game was violate and should have not been played by a young person.