in a surprise tactic, the trial was only for the murder of cynthia mclelland. why not try the murders at the same time? >> what if something went wrong in the first trial. we wanted to be able to try him twice to make sure he got justice. >> kristina sat in court and had to relive the deaths of her parents. what gave you the strength to go to court every day? >> you show up for the three people who gave their lives for something good. they did what they were supposed to and they died for it. >> this is my chance to tell you the story the murders of mike and cynthia mclelland. >> the prosecutor bill wirskye thought of he proved eric williams had killed cynthia, that would show he killed mike. >> the story of a massive law enforcement investigation. federal agencies working together to build an airtight case. >> one of the first witnesses? tomlinson, dallas police officer and friend of the mclellands. cj told the jury how he and his parents found the mclellands. >> i took a couple more steps inside the residence. i was hollering for mike. mike? mike? >> for three