These people were elderly, established, had rental properties, land, income, and they obviously had enough money to pay the taxes and sustain all of it.
Word of them having a safe in the house could have been passed down between laborers who had worked there previously, and the thugs that eventually did the home invasion.
To a murdering thief, intelligence info. like that is priceless. As we all know, it doesn't mean jack-**it as to whether or not these people had a cache of money and valuables in the house. But to these types of brainless insects, that information is priceless. Minimum wage laborers talk, and some of them talk a lot and try to make themselves appear a lot more important than they really are. If one of them was in the house at some point in time, and saw a safe in the corner of the closet, then that could be the source for this entire caper.
As is the case with most of these lower-than-worm-dirt types, they were hoping for an easy payday. That didn't happen, and the Chumney's were killed because of it....... "mistaken assumption"
Personally, I hope when they catch up with Clark, they either shoot him with a silver bullet, or drive a stake through his heart. Either way is okay with me. The worst thing that can happen is for him to go on trial and start complaining about how his Daddy spanked him too much and how his Mother forced him to go to church. I hope LE saves all of us the anxiety and absurdity of a trial.