If, in fact, DW didn't dispose of the body, that would mean someone else did (unless you believe she wandered off into the desert and died). Now, one theory would be that the person who dumped the body was DW's confederate in crime. But, I think a simpler and more likely assumption would be that the someone is the real killer, and the physical evidence has other explanations (e.g., an attempted frameup).
By the way, I seem to recall one of the victim's parents' circle of decadent friends is a retired detective and thus wise in the ways of murder investigations (not to suggest anything, of course).
Assuming that someone else did dispose of body would that make DW innocent or an accessory ?
BTW, that FRIEND was ON THE SCENE right away, directed the VD's what to say and do, and also happened to be a CLOSE PERSONAL FRIEND of the DETECTIVES that investigated the case (guess who).