Anything is still possible of course. But if it was murder- suicide, isn't there a problem with fingerprints? Let's say, for example, that S was the shooter, let the gun fall where it may, and didn't care about fingerprints. He wasn't to know if the gun would be found, or possibly hidden by a friend. So that gun may have his fingerprints on it, or someone else's, or been wiped completely clean. Or - would he have worn gloves? Can't imagine him taking them off afterwards, or his friends for that matter. We need to find out more about the gun.