peggy thomas. in those last dying days of 2003, russell douglas' family had no idea how large that name would loom them for them in the months and years to come. [music playing] coming up, detectives get a call from a mystery man who says he knows who the killer is. but getting him to talk won't be easy. it sounds as if he's afraid for his own life. he said, if i told you what i know, the shooter's going to know that i told you. josh mankiewicz: when "dateline" continues. [ refrigerator clanking ] [ refrigerator knocking ] the moment you realize your fridge is trying to tell you something. at lowe's we sell more appliances than anyone else so we can help you pick the right one. ♪ lean on me, when you're not strong ♪ ♪ and i'll be your friend ♪ ♪ i'll help you carry on ♪ ♪ lean on me. by the spring of 2004, detective mark plumberg has been working the phones and knocking on doors for months but getting nowhere. i actually decided to just start over and do the entire investigation from step one, all