Doesn't a dead body start to smell relatively soon? A dead person in the heat of August in Texas would start giving off a lovely odor within a day or so. The fact that she hasn't been found leads me to believe she ended up in a dumpster or something that was already smelly. Him driving back to Shops has me wondering if he dumped her back there (there are several dumpsters in SOL and the surrounding areas, the mall, etc) thinking if she was found he'd be able to be all "oh I went right home" and have it end at that.