First search result in Google. Black market for pot growing in CA at the expense of the legalized market.
The violence in the 1930s WAS caused by the prohibition, sure it had lasting effects but ending prohibition was still the right move.
No, the violence was caused by criminals funded themselves primarily by breaking prohibition laws. If violence was caused by prohibition, Utah would have been the most violent state in the nation for most of its history, since prohibition was the law in most of Utah for most of its history. It still is the law in parts of Utah.