>> reporter: what was he doing during all that time? the state argued he was staging the scene. detectives saw what they thought were wipe marks on the stairs. to them, it was an attempt at a clean up. and there were those two wine glasses on the kitchen counter suggesting an evening of maybe too much drink, followed by a tumble down the stairs. thing was, kathleen's fingerprints weren't on either glass. in fact, the prosecution said, kathleen's blood-alcohol content was low enough that she could have passed a roadside breathalyzer test. >> she wasn't drunk. she wasn't intoxicated. um, she did have a little in her system. but not enough, arguably, to have caused her to not be able to walk up stairs. >> reporter: was the writer of fiction, making up yet another story, covering up murder as an accident? but, if kathleen was bludgeoned to death as prosecutors thought, "problem." investigators hadn't found the murder weapon.