I realize I am WAY late in the game...or trial, but I agree with this so much. Under the best of circumstance (if you are a murderer) there is SOME minimal forensic or biological evidence of a murder. He used a sledgehammer on FOUR people and there was none. I find that unfathomable. Criminalists can go back years later after New flooring, multiple coats of paint, countless cleanings, and still recover evidence. I haven't seen any definitive evidence that they were killed in their home, and no sign of a struggle. I can't imagine killing 4 people and no one struggles, screams, tries to break free etc. I just don't see the home being a murder scene.
ETA I have followed and read the exhaustive threads since the beginning. Fascinating discussion.