Dum Dum Dugan is the most accurate answer --- he is the agent that first puts hands on the sniper to arrest him. I would also have accepted Nick Fury (also in the room, and in command), or just SHIELD in general.
Great job! Out of curiosity: did you pull a copy and flip thru the story for the answer, or do you have one of those memories that can dredge up this stuff?
I had to research this one, although aweforone found the cover faster. So I'll give him my 1/2 pt. Not sure if he's still here, but I'll put this one up to stew on.
Title and issue?
Western Killers 59 (no number)
Jack