The monster stands, transfixed, staring at the dead police officer. It starts jerking at his body as if to check that he really is dead. It then pulls him out of the chair and starts dragging him across the floor.
The monster is half human half animal. The intended meaning is that the monster starts shaking the body without pulling it anywhere. Can I use "jerking" and should it be followed by "at"? Or does it sound like the monster can't control its hands?