It was BILL LIBBY that had been (apparently) part of the swappers club, who handled the donated money for the Danielle Recovery Center, who POSSIBLY could have been the one calling the search teams and telling them to recheck the Dehesa Road area.
Maybe He went to Dad's the night Brenda,Denise,Keith, Rich, and Westerfield were there. Expected to have Brenda to himself. (His wife was out of town)
When he thought Westerfield was horning in on his territory, maybe he went back to talk to Damon.
Maybe Damon was off playing bumper cars with a female neighbor when Libby stormed into the house. Maybe...... you take it from there.