Maybe it just accidentally fell out? I mean frankly if one is being professional he's not going to have his ID on him when he goes to carry out a plot to kill the newspaper staff of a well read periodical. Unless of course he wants to make sure he gets credit for it even if he gets killed in the process. I imagine then in that circumstance one might cover his face so that if he does get away with it he can go do something else.
Of course the reality is we can makeup any believable sounding theory to wrap up what we know into a nice package that makes, sense and fit's our own opinion seeing as how the only people who could prove us wrong are now dead.
