It seems that there has got to be more involved in this loser's rampage, than simply methamphetamine. How much of this stuff did he take, that he was not merely all buzzed up, but actually hallucinated that the child was a bug as reported in the story? Which was yet not sufficient to kill him with a heart attack or stroke?
Why is it so hard to believe that a drug, designed to totally screw up your perception of reality, would cause a normally responsible person to do unimaginable things?