From Heavy.com...

A group called Far Left Youth wrote on Twitter, ?To be clear, the #stemshooter wasn?t a leftist. One of our admins new him personally and knew that he had no love for socialism. What was done was evil and totally out of line with any leftist values.? The group labels itself as ?Youth led grassroots group meant to educate Coloradan youth on socialist theory/history.?

That was quick.