It establishes how careful his behavior was during those three months. Obviously he was not famous for murder during that time, but it might lead us to believe that a person living on a post pandemic world and seeking to remain anonymous might have chosen a mask at Mc Ds? For that matter… why not on the sidewalk where the event happened?
I’m pretty cynical and I’m nowhere near this cynical.
Is your interest in this “the guy in custody is an imposter” theory is because we want so much for the actual act-doer to still be out there? I confess… I like that world. But a “hero” arising to assume the shooter’s identity feels even more fantastical than my original musing that covert agencies are trying to hide their existence by having a wage slave take credit for calling this in.
This story has parallel construction written all over it.