dylan is a people pleaser. i know my boys. they're drug addicts. they're not murderers. >> reporter: but grand jury says that's exactly what they are. zack adams autry are indicted for murder. >> decatur county grand jury handed down indictment of especially aggravated kidnapping and first degree felony murder. >> reporter: recognizing dylan's weakness as a witness, authorities turn to shayne austin. he's not charged. instead they offer him immunity in exchange for testimony. but he says he can't answer the most important question. where's holly? >> we still didn't have her back so for me, even then, i think there was a part of me that still didn't believe it. that all changed on september 7, 2014, a sunday when two ginseng hunters find partial human remains including a skull at the foot of a cell phone tower in this wooded area off interstate 40. the very area where holly's phone had been pinging. and just six miles from zach adams's house. >> confirmed they found bobo's remains. >> reporter: where were you when you got word? >> we were at the mall in jackson, tennessee. and i will never forget that. i once again got that same, it's her feeli