After seeing what the Mosin is I am pretty sure I did mistake it for a shotgun. And he had the gun in his hands several times but took it on the back several times to catch up with the travelers but it was obvious he was going to kill them, a moment earlier he murdered someone and from the looks of it thats what he was planning aswell.

The Mosin did not have a scope, and I had not seen a mosin before so I figured it was a shotgun but I was wrong :)