>> reporter: the facts were stark and ugly. one night in november, 2006, while her husband was away on business, michelle young was attacked in her own bedroom and brutally beaten to death. her body discovered the next day by her sister meredith along with her 2 1/2-year-old daughter cassidy, who had been left to wander in her blood. for the investigators who set out to find her killer, no way to get those little footprints out of their minds. sergeant richard spivey, lead investigator. >> those of us that work in law enforcement, this is our profession, but we're also parents. that certainly strikes a different note with you when you see something like that. >> michelle's husband jason, a medical software salesman, was 170 miles away the night of the murder. even so, investigators had to look at him. >> we know he was the last person to talk to michelle that night. and he was also the reason why she was found. he called meredith fisher to go to the house. >> reporter: jason young's business trip that night was routine.