This was premeditated to at least some extent. For example, even if Sam snapped and killed all three women ( I do not believe he snapped, not at all) there is still a presumable cooling off period where he should have realized what he had done and gotten out of dodge, instead of hanging around and laying in wait for the father.
I think Sam teetered between being petrified of getting caught and not giving a damn. His attitude probably changed by the minute. The details in the warrant lead me to believe that he DID try to clean up some of the blood at some point, though perhaps that was just in the rooms that the police could have viewed from the doorway or however the house is layed out.
I know there has been a definitive report that no sex abuse occurred, but I am still unconvinced that news is forthright. The warrant states that panties were collected as evidence, Sam was forced to submit two oral swabs, and a blue sundress was found under a chair in the den.
Sure, he probably just grabbed whatever he could find to sob up blood, (paper towels, towels, clothing, etc) but I still do not believe that there wasn't at least the slightest bit of a sexual element that presented its self during the course of the few days he spent alone with those bodies. Remember, Dennis Rader and David Berkowitz didn't rape their victims or commit acts of necrophilia, but they both admitted to masturbating at the scene(s) of their crimes.
