WATCH: After 3rd Yosemite murder victim is found, suspected killers are apprehended: Part 6

WATCH: After 3rd Yosemite murder victim is found, suspected killers are apprehended: Part 6

Transcript for After 3rd Yosemite murder victim is found, suspected killers are apprehended: Part 6

just how twisted. As winter merges into spring, the entire valley just seems to come to life. Everything turns green again. It’s a completely different feeling. It’s March, 1999, and this spring is different, because there is a palpable fear in yosemite park. A very mysterious story. Three people have disappeared. The sounds were last seen near the yosemite valley where the trio had been visiting. In February, Carole Sund, and her daughter Juli, and their teenage friend silvina pelosso had gone missing from the cedar lodge. I can’t imagine how three people in a red car could disappear. This doesn’t happen in the national parks. There was a sense of panic. There was nobody here. Even the locals stopped coming in. You can’t overstate the sense of fear there. Everybody was afraid, everybody wanted to know what had happened. But there’s still no sign of the bodies for about a month. Until a hiker stumbles across a burned-out pontiac. We have recovered two bodies from the trunk of the vehicle. When the FBI announced that only two bodies had been found, that stumped everybody. I urge anyone with information to immediately call the FBI tip line. When they realized it was silvina and Carole, then the big mystery was, where’s Juli? Investigators in California continue searching for the third of three women who disappeared from yosemite national park. Two bodies have been found, but there are still many unanswered questions. For about a week searchers combed the countryside, the roads, the ditches, the rivers, everywhere near that car. But no Juli. Oh, my god, she’s out there. She’s being held prisoner. Something terrible is being done to her. In late March, the FBI got another big clue. We are pursuing significant and potentially very viable leads. This one came in the mail. And when the letter was opened, you see a lined paper, and on the top it says, we had fun with this one. And there’s a crude map, and the map shows route 120. It shows vista point. It shows don Pedro reservoir. And it’s about 40 miles away from where the car was found. They bring up a cadaver dog, and within ten seconds of going to where this map points out they find Juli’s body. Earlier this afternoon, investigators discovered the body of a homicide victim. The body of 15-year-old Juli Sund was identified earlier in the week. When you saw where Juli Sund took her last breath, the gravity of the story really hit home. Just to think of her being alone, away from her mom and silvina and wondering what’s happened. It was terrible. Francis, was that also for you the hardest part? That, that was the end of, you know, any hope. I’ve told the family that we won’t stop until we find out what happened, until we’ve resolved this. So, as we move into the summer of 1999, yosemite’s getting back to Normal, and the tourists are coming back. And now, five months have passed, there has been no more murders. So the sense around yosemite was that it was safe. It was safe because the people responsible for this horrific crime, according to the FBI, were in custody. When they made the announcement that we have the killers — They believe they have the killers in custody. Huge. Absolutely huge. We do not believe there is anyone else on the loose who is not in custody. These two men were half brothers. They had criminal records. They were violent offenders. So there’s a sense of relief that, “Hey, we got these guys. Everything’s okay.” With the FBI’s assurance, relatives sense closure is near. Once they went down that road, it seemed like they just kind of had tunnel vision, and they weren’t looking at anything else. People may have thought the right people were in custody, and they certainly wanted to believe the right people were in custody. But they weren’t the right people. Cary Stayner was still working here at the lodge, he was still living here on the premises. He was still an active member of the community. He was not an unknown quantity. People knew who he was. He was not someone who hid. We didn’t see him as a suspect, he didn’t raise alarm bells for anybody. Stayner was free. I mean, he had gotten away with triple murder. On the more westerly aspect of the park is a little area called Foresta. You can look down and see this gorgeous meadow, and it’s called big meadow F good reason. Down in that meadow is an old house. It’s called the green cabin. It’s owned by the park service and it’s leased out for a dollar a year to the yosemite institute, which runs educational programs throughout the park. Living there in the summer of 1999 was a 26-year-old woman named Joie Armstrong. She was really kind. And she was sensitive. She was loving. She was generous. She was smart. Joie was a naturalist at yosemite. Her job was toildren and teach them the nature of yosemite. I asked her if she was ever afraid, and she said, no, we knew they had suspects in custody. She had memorialized it in her diary. At one point even wrote, “The monsters are gone,” meaning the FBI had gotten the people who did this. And they were behind bars. But it turns out the monsters weren’t gone. Cary Stayner was very close by. It’s tough to quit smoking cold Turkey.

This transcript has been automatically generated and may not be 100% accurate.

Read More