Well, for the body being easy to discover it sure took a long time by my standards to find her. And even then look how much evidence was lost in that period of time. The body placement served the killer's purpose. We all know that cause of death cannot be definitively determined, plus any evidence of a possible sexual assault also destroyed. I'd say the killer picked a pretty good spot----from his perspective.
The body is hidden for only until the next illegal dump or human scavangers pick through the garbage. The body could have been discovered the next day.
And since they SEARCHED that same area ONCE already, is it likely the body wasn't there the first time? The reason it took so long is the killer finally put it where an idiot could find it? Because he was so tired of the inept job the police were doing going after the wrong guy anyway and taking away the spotlight?