He had an encounter with Audrey before about his smoking.
In See No Evil, Mara posing as Audrey walks up to Sam asking to see his backroom. When Sam asks why, "Audrey" says it's police business. He takes her to the backroom and is confused to what she is looking for. When Sam gets worried about "Audrey"s actions, he informs her that he is calling Nathan. This is even Mara shoots him in the head, killing him.