I'm looking for a movie that I wanted to watch, but never got around to it and no longer remember much about the movie.
In the theater trailer there is a serial killer who carries some kind of mechanical device. He holds the small device in one hand, a cable or tube comes from the device and goes to a canister he holds in his other hand. To kill his victims he holds the device up to their foreheads. I've often wondered if this was something used to kill cattle?
The trailer never actually shows what happens, but the context is that his victims don't realize the danger of the device.
One victim shown might be a sales tenanted at a gas station in the country, and I think in one shot the killer is shown using the device to pop the lock on a door.
The time period seems to be in the present, in the country and there is either a sheriff or detective trying to catch this killer.
The killer has a calm and quiet demeanor.
This film came out a few years ago (I think).