Who is laying on the ground when the camera is knocked over at the end of the Blair Witch Project?

The floor. No one was holding it at the end, the camera was dropped on the floor.

The real answer you looking for is that its up to the viewer to decide. It could be the witch (it is NOT the woman as you can hear shes not holding the camera or you would hear her screaming much louder. It could be Mike who did this all just to kill them or it could be the witch controlling them all. It's just a movie and the joy is in what you take away from it and your own opinions.