Reefer Madness 3.0. Cannabis is the ONLY cause?
Marihuana is not at all harmless.
There is a reason why it was banned and should be banned still.
The current marihuana legalization in many states actually gave us more knowledge about marihuana effects and they are a lot worse than previously imagined.
A lot worse than smoking tobacco!
However the killing mentioned above is chicken and egg problem.
All those cases were horrible cases of schizophrenia and the killing were definitely caused by schizophrenia (Lots of schizophrenics are unfortunately let to roam the streets instead being locked in mad houses.)
Marihuana and schizophrenia go side by side, but
there is a disagreement, if marihuana use causes schizophrenia, or schizophrenia causes extensive marihuana use!