Here's Ricky outside a German shop called Galeria Kaufhof. It's already taken every single video game and DVD with an 18 plus rating off the shelf.
As part of his investigation Ricky found that loads of German magazines and newspapers were writing about whether or not 18-rated games caused people to played them to be violent.
This computer expert said he thought computer games were being unfairly blamed for the shooting, as the reasons the shooting happened were complicated.
Ricky talked to some children in Germany to find out what they thought. Most said they didn't watch 18 rated games - but some admitted borrowing older brothers and sisters'.