and her nose and suffocated her. >> in light of the confession, forensic pathologist dr. mary case examined the skull. she studied the small wound on the back of the skull and concluded that it was not the result of an accident, but rather, the result of blunt trauma to the head. >> this is a very limited area. it's pushed inward. and we tend to see this kind of depressed skull fracture when you strike the head with something that has very forceful impact over a very small striking surface. a hammer would be a good example of something that could do that. it is a tool. it is meant to strike. and all of the force is directed on to a very small striking surface. >> based on the forensic evidence and parts of nyhuis' confession, prosecutors believe that richard and bun chee argued one night in the basement of their home. >> we're not moving! we've been through this before! we are not moving!