>> we the jury find the defendant matthew scott sullivan -- >> when dateline continues.means... the smoothing benefits of retinol. are now for your whole body. plus, fast-working crepe corrector diminishes wrinkled skin in just two days. gold bond. champion your skin. nexium 24hr prevents heartburn acid for twice as long as pepcid. get all-day and all-night heartburn acid prevention with just one pill a day. choose acid prevention. choose nexium. keith morrison (voiceover): : for all the evidence stacked >> for all the evidence stacked up against matt sullivan in the murder trial defense attorney mark's deposed was confident. because he knew, at the heart of the prosecution's case, there was a contradiction. labeled with a grim clinical term. the post morton interval. >> there were two separate medical examiners we examine the body, they both found and then testified to the fact that the postmortem interval, which is the period of time between the autopsy and what science determines to be the time of death, they both found that that was a 30 to 60-day window. >> meaning