It's never wise to determine one's philosophy in a heightened state of emotional arousal. It often leads to inconsistency and a lack of logic. Stories like these are tragic, but they must be statistically thrown into the aggregate if you are to make an informed decision.
I think the death penalty should be acceptable for especially heinous crimes where the burden of proof should be beyond the shadow of any possible doubt. Then again, realistically, and always wary of the government as I am, I doubt they'd be able to handle it as such. So we might as well play it safe and eliminate the death penalty, for fear that the government may be negligent or abusive toward their power over a person's life.
And I might also note - to pre-emptively dispel future arguments - that the notions that the death penalty is "backwards," "outdated," "absurd," etc., make no sense, and are not actual arguments. In saying that, one is essentially arguing that he is against the death penalty because he is against the death penalty.
Creativity can always cover for a lack of knowledge.