he determines that although zach adams' phone may have been in the same place as holly bobo's at timesme, at other times that day, zach and holly's phones were far apart. >> at 8:17, holly's phone is over in this area. and at 8:16, zach adams' phone is over here, and they're miles apart, okay? >> reporter: but it's not just about creating reasonable doubt -- thompson is shooting for reasonable certainty that the real killer was someone else. for assistance she turns to terry dicus -- the former lead investigator removed from the case because of unwavering belief that his old nemesis terry britt is the predator who murdered holly. >> in your opinion, what is the strongest evidence implicating terry britt? >> he's the kidnap and rapist in decatur county. he's the one that would be willin' to do this. >> reporter: aside from his notorious rap sheet, you'll recall that britt had a wafer-thin alibi, and the cadaver dogs alerted on his car. >> who has human decomposition on two of their cars and four of the tools in their shed? who has that? zach didn't have that. shayne austin didn't have t