up until that moment. >> reporter: they placed him around emma's house. >> he placed himself in maryville had clearly told a lie about where he was? >> yes. >> the picture that we painted of riley gaul was a deceiver. somebody that was phony that -- i mean, you couldn't get the truth out of him if you tried. >> reporter: but on the first day of trial, riley's defense attorney wesley stone up-ended the state's case with an unexpected admission. riley was there, did fire the gun, but it was not murder. >> that was a fairly stunning claim. >> reporter: from the gallery, veteran crime reporter jamie satterfield saw jaws drop. >> what he said was that riley never intended to kill her. and in fact, assumed he would not kill her if he shot through a wall. >> we'll ask you to find mr. gaul guilty of reckless homicide. >> reporter: not premeditated murder? >> right. >> in tennessee, that's two to four years in the -- >> reporter: wow. >> penitentiary. >> reporter: that would be a huge difference -- >> yeah. >> reporter: all of the states' preparation went out the window. >> the case went from a wh