I agree. I've worked many a one-hundred plus hour week and never thought of killing anyone. Lack of sleep was not a factor in this crime, especially as evidenced by the planing and preparation before the trip began.
In both your cases, you were getting at least SOME sleep - on a semi-regular schedule, correct?
Try going four days with NO sleep and then tell me how normal you feel - if you're still able to type, that is.
Try going two weeks without sleep and let us know if you can still remember to finish brushing your teeth.
The type of sleep deprivation I'm thinking of goes way beyond what you've described.
http://www.google.com/search?hl=en&q=Sleep+deprivation+hallucination
The original reason for my posting on this thread was to provide an alternate explanation to someone the speculation that the behavior in question was Meth induced.