I tend to think it's more than 1 guy.
That county is full of people and a lot of eyes watching.
The shooter needs time to set himself up and have a quick exit.
The retort of the rifle would draw attention... so would the smoke.
Whatever... the dude is a professional killer and the cops don't have a clue.
Don't rule out terrorism.
It's still stuns me everytime a rational post shows up.;o)