I can't help but think, that many people are giving DG waaaaaay too much credit. He is far from a mastermind.... He used his own vehicle to case and carry-out the homicides, obviously left trace evidence at his home and/or truck, and was apprehended defying a court order, returning to where evidence had been collected. Also, unlike many homicides of this nature, he was arrested after a very short period in the investigation.
Therefore, I can only surmise that the disposal of the victims was more simplistic in nature such as dumping. IMO, that is why LE have focused their search where they have. The suspect has failed at everything he ever did.... This time is no exception.