You in no way you know whether or not if that is bondo, you’re just playing detective pretending to see things that the police somehow missed and you are making an swing assumption that the entire case relies on that piece of evidence. You don’t know all of what evidence that has been gathered. For all we know the police probably have surveillance video of him from the incident back to the hotel. The police don’t immediately necessarily show all the evidence to the media or the perpetrator, they will give the perp the chance to confess then if he doesn’t they cook him with the evidence.