Why is it odd? If the gunman is going to be masked -- itself an indicating prior intent and planning -- a shotgun seems to be the result of planning as well.
I'd think that a load of buckshot would be a better guarantee of lethality than would a pistol.
” Why is it odd? “
Not very often used as a weapon of choice for a hit now is it?
Even if it was a shorty, it is a little bulky.
Just what I was thinking. If he used 00 at close range, it would be like shooting him with a dozen or so .22s at once.
Like you said, whoever shot him really wanted to make sure he was definitely dead. Which is what you must do if you are a hired hit man.
Not to mention the difficulty tracking the weapon.