Strikes me that without prohibition they might not have caught poor Marie Davis killer (the 15 year old Christchurch schoolgirl). He was arrested for possession some days before getting collared, which appears to have helped Police in making their inquiries.
So many violent offenders smoke - womens refuge can confirm this, so it needs some research re chicken and egg. Case in point would be Tim Shadbolts happily divorced wife (Sunday News did an item on her hellishly violent marriage to happy Tim). Greg Newbold could be the person to investigate whether pot is les than mellowing for some.
I find it mellowing but know some DO NOT. Could be something to do with the most dangerous subsance known to man - testosterone lol. As a previous domestic violence victim I feel that pot can reduce inhibitions, letting testosterone take over and control the man or make the mouse mighty - in some cases. I guess the dead like Marie can't tell us exactly how it went down. But increased sex arousal /power in male strength etc seems like it could lead to trouble - in the psychologically twisted who would not handle toking so well.