Or perhaps you are an insane fuck.
Anyone can go and talk to the survivors and/or loved ones of the dead. You can also go talk to the injured. Kind of hard to fake a gunshot wound and a trip to the hospital to treat it.
But because you are such a crazy fuck, you won't do it, you will stay safe in your mama's basement.
As to your whole stupid argument, nobody arrested the shooter before he went on his rampage. He was presumed innocent until he committed the crime.
Wow, you were able to make a t-shirt over at zazzle.com with your mental issues?
Well done.