Video games do not cause violence. Research indicates the opposite. This is a scapegoat that is commonly used by conservative voices who are pro-gun. We need gun reform.

They use time-series modeling and also instrumental variable modeling, and either way you slice it, when a very popular violent video game comes out, violent crime goes down, not up. The researchers believe the method is what criminal justice scholars call “incapacitation” — if you are sitting on your couch playing video games you are, by definition, not out on the street making trouble. When it comes to ways to spend time that mainstream society finds uncontroversially wholesome, this mechanism is widely accepted. If you have teenagers doing summer jobs, attending after-school classes, or participating in recreational sports leagues, that keeps them off the streets and out of trouble. It happens to be the case that video games are a more stigmatized pastime than playing sports, but the basic mechanism is exactly the same. If you’re busy gaming, you’re not committing crimes. [via: Vox]
Understanding the Effects of Violent Video Games on Violent Crime by Scott Cunningham, Benjamin Engelstätter, and Michael R. Ward