For to have a death on your hands, in your own opinion, will always be with you. The thing that you have to do is try and get over the death yourself. You have to realise that you in no way meant to hurt him, and it was very unfortunate that experience had to happen to you. Things happen for a reason, and in all honesty, if that guy hadn't have died then, he probably would have sooner or later if he was carrying a gun.
It isn't your fault, the courts decided that also. But the guilt may perhaps be making you to hallucinate him, or you just perhaps you saw someone else and someones shadow. But if its still really bothering you (as admittedly it would do me), may i suggest counseling, because perhaps verbally discussing whats going through your head in a confidential and safe environment might perhaps make you realise yourself you're a good person. pm me if you wamnt to talk more-
xxx