I remember a scene where dogs, probably two or three Dobermans, are left in the back seat of a car. They see another dog playing outside. They unlock the car door, open it, run over and kill the other dog, then go back into their car, and shut and lock the door.
I thought maybe they were hell hounds from the Omen series, but I just watched all three and that's not it. I think maybe they part of an experiment to increase intelligence.