she just never got into any trouble at all. so that s what makes this so much harder cause nothing like this should ve ever happened to her, you know. reporter: especially to her. especially to her. reporter: what was done to shelley nance, just 20 years old, was viciously ugly. that it was murder was all too obvious. the girl had been attacked as she lay probably asleep in bed. her killer stabbed her again and again and again. over 40 times. in the back. she was stabbed in her back. she was stabbed in her neck behind her head. i mean this was brutal and this was savage. reporter: overkill, said detective paul ellzey. as will be clearly apparent, detective ellzey has deep roots in old-fashioned police work. starting as a kid, then 36 years with the dallas p.d. dad was a cop. wife and sisters, too, worked in law enforcement.