It's interesting that the link that was @ Harvard with a pdf of the results (that Harvard published...) is now a broken link.
Here is a working copy: https://www.garymauser.net/pdf/KatesMauserHJPP.pdf
Gary Mauser who is also a Candadian criminologist. Interesting indeed. https://www.sfu.ca/~mauser/
They are caught up in a legal dispute that is still carrying on.
Linking something to them is no better than a fortune cookie.
https://www.forbes.com/sites/kalevleetaru/2016/12/22/the-dai...
"This would explain why shootings occur in “gun free zone” schools and movie theaters rather than in police stations or gun clubs."
Seriously HN?