It's good that you acknowledge that fact. However, I'm not sure how his age enters into the equation. Are you claiming that at 17 he wasn't capable of understanding that pumping 40 bullets into three fisherman is wrong?
However, a parole board, who I feel certain knew much more than any of us about the situation, felt that Dr. Krueger should be released. Unless you know the entire story, I don't think you should be so quick to judge.
What's to know? Did he shoot three fisherman 40 times in self defense? It isn't as though he stumbled upon these three in bed with his wife, you know...
I knew Dr. Krueger and he was an excellent professor and a good person. Did he made a terrible mistake, absolutely! Should he be held responsible and punished for that mistake, absolutely. Was 12 years in prison enough? The parole board thought so...
The parole board thought he wasn't in need of further prison time. That's an entirely different question than the one Penn State needed to make, regarding whether a convicted murderer should be hired instead of someone with a clean record.
At a minimum, university reputation is a good enough reason to automatically exclude anyone with a felony offense from the teaching ranks. Certainly the university has an ethical responsibility to its customers as well.