the house when heidy was shot, and there was no evidence of an intruder. >> i felt like they thought i did something. >> reporter: soon after he arrived at the scene, sergeant bill crook did begin to have his suspicions. >> we're telling him, conrad, back off. the paramedics are here. back off. and he wouldn't. >> reporter: he was what, moving around? >> yes. >> reporter: keeping paramedics from being at the body? >> yes, sir. >> reporter: there were other scenarios that needed to be explored, like accident and suicide. that's where detective tom wallace came in. >> there had been a number of theories. we obviously are going to exhaust them. that's going to happen. >> reporter: the medical examiner didn't make wallace's job any easier. his preliminary finding -- heidy's manner of death could not be determined. so wallace tackled each theory one by one. accident seemed hard to believe. thanks to conrad, heidy had firearms experience.