darren wyatt was not going to quit before i filed a case or i died or he died i guess. he was dedicated to this. >> if murphy declined the case a third time, the cathy torrez case would certainly go from cold to dead. what would he decide? no one understood the stakes better than cathy's mom. >> darren had told me that we were going to meet with the d.a. my interpretation of it was he was going to tell me there was nothing they could do. coming up. a key piece of evidence arrives. better late than never. >> how long had they known that? >> a couple of months at least. >> they what, forgot to call? >> it isn't the smoking gun. when "dateline" continues. alright, off you go.