>> reporter: and then, a gunshot. >> it felt like i had been hit in the back, which was confusing to me, 'cause i knew i was looking at a gun, but it felt like somebody hit me in the back. >> reporter: in the confusion, greg said he or jason yelled "run," or possibly "gun." >> and while we were running, i heard about six more rapid gunshots. >> reporter: the prosecution argued diana paid weldon mcdavid to kill greg that night. and it seemed weldon may not have been the only one diana approached with this goal in mind. >> do you solemnly swear -- >> reporter: there was an unlikely witness against diana, a woman who reluctantly shared her story with prosecutors. her own aunt, diana clark. >> diana said, "you need to promise not to tell my mom or my sister. can you promise me that?" and i said, "yes." >> reporter: then, aunt diana testified that on christmas day