Transcript for Missing nursing student Holly Bobo's remains are found by ginseng hunters
Reporter: Ever since that April morning when holly Bobo vanished into the Tennessee woods, the tips poured in. The more the investigation foundered, the wilder the speculation. Psychic visions and sightings. Holly becomes a phantom haunting every dark corner of Decatur county. Citizens report, she's being held captive in a barn, no, tied up in a warehouse thrown down a well. One woman claimed to have been there the night holly was taken. Another fella claimed to have her in the basement. Reporter: Police are tipped off early in the investigation to four small time criminals, brothers Zach and Dylan Adams and cousins, Jason Autry and shayne Austin. They were essentially best friends. They did everything together. Reporter: Zach Adams is one of those people in town allegedly shooting off his mouth, taking credit for holly's disappearance. Zach would tell people, "You're gonna end up in a hole just like holly." They would make comments everywhere that Normal people would not make. Reporter: So do they come to the top of your suspect list, somebody to check out? They were brought up early and often. They were brought up by people that know that they're just bad people, into drugs. Reporter: Reputations that draw the attention of the bobos, who by now have begun doing their own police work. They track them one by one and ask for a chat. Reporter: What did you say to these people? I asked them did they know anything about our daughter's abduction? Of course, they all denied it. Reporter: Was any part of you afraid? No. I guess I would have fought goliath. You know? I just had no fear. I was trying to find my daughter. Every single moment of her life since holly went missing has been devoted to that. She never gave up hope. Reporter: When you went to interview these two brothers and their friend, Jason Autry, how did they strike you? They appeared believable to me. Reporter: Did they have alibis during the time of the crime? Alibis that checked out. Reporter: But then Dicus is taken off the case, and investigators return to that foursome. Unlike britt who Dicus thought acted alone, four suspects provide an opportunity to break the case. Detectives just need one to turn on the other three. Police begin a series of at least six interrogation sessions over eight months, with the weakest link Dylan Adams who quickly admits being with holly Bobo the day she was taken. Describe, what was she was doin'? What did she look like? What was she wearing? She had long pants on. Pink shirt. Okay. Reporter: Of the four suspects, Dylan is the youngest. And his mother Cindy Adams says he has intellectual disabilities. He even has trouble telling time. And if you lie to me one time, I'm getting up and walking out. And we're done. Reporter: As you watch that, as you watch that videotape of your son, what do you see? I just see someone Bein' bullied into saying' something' they didn't do. You've destroyed evidence. You withheld information. That ain't how this works! Was holly Bobo kidnapped? Yes, sir. Was she raped? Yes, sir. Was she raped by you? Yes, sir. Reporter: After numerous sessions with halting one word answers the frustrated agents seem to realize Dylan will not make a good witness. Dylan doesn't give them any of the mysteries about who took holly, where she went you know when she walked into the woods, where she was killed, where her body had been. Reporter: Even so, detectives cobble together the following story from Dylan. He tells them his brother Zach, Jason Autry and shayne Austin kidnapped holly. Dylan says all four of them sexually assaulted her at Zach's house. As for who killed holly, in one version he says it was Zach, another, it was Autry. I think that he was just tryin' to get through it. And he really didn't care what he said. 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 and Jason 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 7th 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 feeling. Just had that same feeling, they're gonna come and tell us that's her. Reporter: Her intuition proven right. The skull is holly's. And there's a bullet hole in it. They have a body. But they lose their witness. Before he can testify, shayne Austin hangs himself in a Florida hotel room. Authorities desperately need a break. There is no physical evidence linking the Adams brothers or Jason Autry to the crime. Even so, prosecutors charge all of them, including Dylan, announcing they'll seek the death penalty. All three plead not guilty. And this guy actually believes them, the former agent in charge of the early years of the investigation, Terry Dicus. Why don't you think these young men are guilty? I don't think they're capable of doin' arithmetic, much less this. Reporter: But prosecutors are confident they can make it all add up.
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