A sociopath
The Herald reports that Burton shot and killed the quad biker simply so he could use his body to lure other passersby. This is pretty much sociopathic behaviour where human life has no value at all. Remind me again the geniuses who said he was fine to be let out.
Oh yeah Burton has also has his wounded leg amputated. Welcome to a lifetime of ACC and invalids benefits after he gets out the next time.