This doesn't bode well for liberal gun control lobbyists - especially the pot smokers. I am aware of some strains of pot that can cause people to hallucinate and have all sorts of weird psychological experiences. Also these days it has been gmo altered in so many cases that people don't even know what they are smoking anymore. BUT that said, I think it still boils down to that you can't change a criminal mind or person with evil deeds to do. Whether they smoke pot or not, whether there is gun control or not, they are who they are. They will do what they set out to do. To blame it on guns or pot is putting the blame outside of where it should lie with the individual who obviously has no morals or ethics to prevent them from committing heinous crimes.
Far more crimes have been committed after excessive alcohol consumption, a legal substance which when abused can completely change a person's personality. Intoxication often brings up violent thoughts or emotions that may have been buried. But the demons already lived within and the use of alcohol, just like the use of pot by those who know they might lose control of their normal behavior and act out violently in their altered state, is a symptom not a cause of a criminal mind.
I think this criminal is the Ted Bundy of pot smokers. Ted blamed porn for his murders. As much as I hate porn, if his mind had not already been warped beyond a normal person's comprehension, he like the billions of other people over time who have viewed porn would have never taken a life.
Trevor Loudon wrote a good article about the Pothead Killer found at the link below ->