As close as this guy is (and beyond, for that matter) the lowest form of life on this planet, I never hope or wish for "extra-judicial" punishment within prison of any form.
He definitely did it of his own free will but I can't help to think that inequality may have played a factor in the whole issue, which is a result slightly of the government refusing to install social nets.
It's something that should be brought up a lot more often when it comes to this and shootings because when people are poor, they'll likely seek to blame anyone but themselves, leaving themselves vulnerable, which leads to those with nefarious intentions to get inside their heads and then you typically end up with these types of situations.