IN the third link shared, I couldn't help but notice this:
"Around one in the afternoon, Boulder police detective Linda Arndt suggested that Fleet take John Ramsey around the house to see if they'd missed anything -- probably just to give the anxious father something to do. After inspecting several rooms in the basement, Ramsey headed toward a storage room known as the wine cellar. It was a door Fleet had opened on his earlier tour, but he hadn't found a light switch and hadn't gone inside. Moving a few feet and seconds ahead of Fleet, Ramsey opened the door and snapped on the light.
"Oh, my God," he said. "Oh, my God.""
Perhaps the only reason Jon "found" the body that morning was because FW was with him, and you can't pretend to be thorough or pretend you didn't see anything, when someone else is right there with you.