The Colley case was solved, and is unrelated, unless it’s the same yard worker somehow. Not likely. I’m sure I’ve posted this here before, but I always wondered if the Dermonds’ son who died, whom they had allowed to go to prison for drug charges after he stole from them and fell off the wagon for years, maybe voiced a hatred for his parents while in the clink and one of his cell mates got revenge on his behalf. Perhaps they had some bond and the person was determined to avenge his friend’s betrayal at the hands of his parents. The son (Mark??)could have told the person where the D’s lived, their routines, about the house and lake. It’s a super long shot, but it’s more plausible IMHO than some of the other theories like Israel Keyes or the mob.