Sorry to sound a bit like a broken record, but I’ll re-state my own theory again:
1) I’ll buy that BC took YY back to his apt. (though I initially disbelieved it, and still don’t comprehend just how he accomplished it!). Then, either when she fought back or when he learned the Astra had been caught on tape, he killed her (within 72 hrs. of abduction). Then stuffed her into a duffle-bag, sheet/blanket, or the like, and in the dark-of-night carried her to the trunk of his Camaro; drove to outer Champaign (perhaps even farther out, but not much), to an industrial or business site during off-hours (little human activity) and dumped body into one of their dumpsters.
2) Since several landfills apparently service the Champaign-Urbana area I’m guessing LE commenced searching the one that took garbage from his own apt. complex — and that alone was probably a daunting task — but that’s probably not the landfill where she ended up (BC would’ve specifically avoided his own apt. dumpsters). I previously mentioned that the two main landfills seem to be in Danville and Clinton; I assume one of those received trucks from Stonegate Apts.; I’d explore the OTHER one (but there are other area landfills as well, and literally, her body may be irretrievable by now for all practical purposes).
3) [I’m also betting cadaver dogs got the scent of death in his apt. and there were incriminating pics on his cellphone; perhaps the ‘informant’ had many more details, not yet released, as well.]
ALL sheer speculation on my part, but I think it very simply fits a lot of the details together.
[originally, I thought he most likely dumped the body in water, but for a variety of reasons, no longer think that likely]