. >> so they sent this tissue to a fellow named mike collin who is a neuropathologist in ohio.nd said, yeah, it's mammal and it's cerebellum. it's the brain stem. >> the cerebellum sits at the base of the brain and is primarily responsible for memory and motor movement. since the cerebellum controls the heart muscle, no human can survive without it. a ballistics expert compared the location of the brain tissue in the camper with the bullet holes. using a two-point laser, he marked the center of the bullet hole and then followed the bullet's path. it showed that the shooter was firing from a standing position. >> clearly few people shoot holding the gun up over their head, and if you realize their body was interposed between that, we only have a few feet to deal with. so it can't be a standing man, for example. it could be a collapsed man or a person nearly down on the floor. >> next, ballistics experts examined the bullet fragment found on the floor of the camper and discovered what was called soft damage. >> it deforms in a very different way than it would if it hit wood, conc