In the Electric Mist (2009)

Dave Robicheaux: In the ancient world, people placed heavy stones on the graves of the dead so their souls would not wander and inflict the living. I always thought this was simply the practice of superstitious and primitive people. But I was about to learn that the dead can hover on the edge of our vision with the density and luminosity of mist, and their claim on the earth can be as legitimate and tenacious as our own.