I don't believe Oswald was a "sadist" in the traditional sense. A sadist is someone who takes pleasure from inflicting pain. The infliction of pain is the objective. Oswald definitely had a screw loose but his behavior was more consistent with that of a sociopath. Someone who is completely lacking in empathy and has egotistical traits. That enabled Oswald to lie or commit murder without any feeling of remorse when he felt it suited his needs. The pain he inflicted in others was a byproduct of his lack of empathy and ego.
A sadist is a person who won't hurt a masochist
