What's worse than learning of the death of a loved one? Believing you know who the killer is, but not being able to prove it. 48 Hours tracks two families who are desperate to find out what really happened when their relatives died. Kristine's Story: In the weeks before Kristine Kupka's disappearance in 1998, family and friends say Kristine had a new man in her life. Darshanand "Rudy" Persaud was her college instructor. One afternoon, Rudy reportedly picked up Kristine at her home. She was never seen again. Did Rudy have something to do with her disappearance? What Do You Think? Do you think Dick Dow and Rudy Persaud are getting away with murder? Add your post to the 48 Hours bulletin boards. Just An Accident? A family is torn apart by mysterious deaths. Nineteen years ago, Steven Dow and his mother Janet were incinerated in a car fire not far from their house. Some people believe that Janet's husband at the time had something to do with their deaths. Was it an accident or something more?