Now what caused the blood in the Van Dam's house?
Well, how about this thought.......
Brenda and kids visited DW, and sold Girl Scout cookies. Did the kids "run" around the inside of DW's house? That's the story.
If the RV was there, kid's would have loved a "tour". Like going to an amusement park. The Palm/Hand print was on a cabinet, above the bed. You mean like how kid's jump on beds, like a trampoline? (Thinking inside and outside of the box!)