For the last 20-years Karen Hull has been haunted by nightmares of what happened to her missing son.
Hull, 59, is also furious the case took so long to be solved, furious that police admittedly assumed her son, Walter Ackerson Jr., was just another runaway and didn't follow up on leads.
"I think the most shocking thing was ... the story that I had been told by a girl back in 1990," Hull told ABC News. "She said she had heard there had been a fight, and my son had been thrown off a bridge. The police never investigated that, they never talked to anyone about it."
Now the detective who is responsible for cracking the case agrees with Hull's assessment.
"I certainly can understand. This was bad police work, unfortunately," Sgt. Mark Meister of the Lincoln County Sheriff's Department told ABC News.
"Some work was done, but at that time they wrote a report saying this was nothing more than another runaway and that ended it. I'm not saying it would change the outcome, but more should have been done," said Meister.
"Karen has every right to be angry and frustrated with what happened, I totally sympathize with her," Meister said.
Meister stumbled onto the Ackerson case and his prodding eventually provoked one of the boy's alleged killers to confess.
But now Hull faces the possibility that, even with a confession, her son's murderers may go free.
Hull said she and Walter tried to start a new life in Puyallup, Wash., after she says she escaped an abusive relationship. According to Hull, her son was suddenly thrust into a much larger school district, and experienced problems with other classmates.
"He was small, and he was struggling with the other kids picking on him. A lot of bullying that back then, just wasn't addressed like it is today," she said.
Walter didn't want to go to school and Hull thought they found an alternative in the Oregon Job Corps.
"It appeared to be a really great opportunity. He thought he was going to be able to get his education and move on and do something with it," she said.
Walter moved 200 miles away to the Angell Federal Job Corps Center on the Oregon coast. She said for two weeks her son kept in regular contact with her and his grandmother, but that suddenly stopped. The last time they heard from Walter, Hull says, he told his grandmother Delores "this place is nothing like you think it is."
On April 5, 1990 Hull said she received a call from an administrator at the Job Corps and learned Walter had been missing since March 24.
"They told me my son ran away to Wyoming with another boy, and I asked them to file a missing person's report and they asked me why? I said because he is 16," Hull said.
Two weeks later, Hull said she found out her son was never reported missing, so she drove the center to speak to a director and the last three students who were allegedly with her son.
Karen Hull Says Police Failed to Investigate Her Son's Disappearance
"They then told me he said he was going to run away, and all his things were gone, and when I met with the boys and the director I found that all his things were there," Hull says.
She was told by the staff and the three boys her son had been drinking and had run away. She then says she met with 20-year-old Troy Culver, 19-year-old Eric Forsgren, and 19-year-old Geoff Calligan.
Hull said the boys told her they had snuck off the campus and traveled to Newport, Ore., to drink beer on the beach and had gotten separated from Walter at some point and hadn't seen him again. It was at that point, Hull says, that Culver offered up something that in retrospect gives her chills.
"After telling me the story, Troy looks up at me and says 'I'm sorry,' and I told him he didn't have anything to be sorry about if my son was drinking and ran away. He told me he felt responsible," Hull said.
Hull said that while she was there she also spoke to a girl, Emma Beller, who told her there was a rumor about a fight between Troy and Walter and that Walter had been thrown off a bridge. Hull said she reported it that to police. Although Hull said Beller's story is noted on a police report, Hull says it was never looked into. Police reports also show that Calligan was never interviewed, and Forsgren wasn't interviewed until six years later. When police did speak to Forsgren, he repeated the same story as Culver.
Hull claims that the police decided her son was just another teen runaway.
"They thought he was just a deadbeat, that he was nothing," she said.
For the next 14 years, she had to live with her nightmares as to what may have happened to her son.
"Mostly you just try not to think about it. You have to go to work and you have to keep going, but obviously there are lots of things in your life you have to stay away from, like shows about missing children," Hull said.
"You have dreams about it, you can't make them stop, but you try to kind of stuff it inside somewhere because you know when you do have to cope with it, you are going to break down," she said.
In 2004, Meister was recently promoted to detective when Walter Ackerson's case file was handed to him. According to Meister, a marine on the East Coast was suspected of molesting a 16-year-old boy and after a search of his computer, Meister says investigators found pictures of Ackerson's missing person's poster.
That lead fell through, but Meister started digging through the old case file and he says he found a lot of unanswered questions.
According to Meister, the Angell Job Corps was rife with runaway reports in 1990, and he thinks that the police were convinced Ackerson was just another one.
Cold Case Was Closed a Second Time Before Confession
"The Angell Job Corps was fairly notorious at the time for a lot of runaway reports and I guess you get complacent. They believed Walter was just another runaway and they didn't do a lot with it," he said.
Meister said one of the most glaring leads left without follow up was the story Emma Beller told Hull.
"Unfortunately that was never followed up on. That was not good," Meister said.
He found Forsgren in the Multnomah County Jail. Forsgren's memory was foggy, Meister said, but it was generally the same story of drinking and getting separated from Ackerson. He got the same story from Calligan.
But in interviewing Culver, something about Culver's memory struck him as odd.
"I got a weird feeling from Troy Culver. He seemed to remember a lot of details, while the others were like 'gosh it's been a long time,'" Meister said. "He had that look, that look like he was somewhere else."
Meister said he next found Beller and reinterviewed her over the phone, but she couldn't recall anything regarding Ackerson's disappearance.
"After all the work I did, we ended up in the same place. I had to close the case back down," Meister said.
He says he called Karen Hull, to apologize to her and tell her once again her son's case was getting shut down.
"I had to tell her I'm sorry, that I had to close it again. That was kind of it, she thanked me for trying," he said.
That was it, until last August when Meister received a call from the Prineville Police Department.
"I get a call saying Troy Culver came in and confessed to killing Walter Ackerson," Meister said.
According to police, Culver was a registered sex offender since a 2007 conviction of encouraging child sexual abuse, and was attending counseling and drug and alcohol therapy. Police say he was meeting with his parole officer when he allegedly told her that he had had beaten a man to death when he was 20-years old and thrown the body off the Yaquina Bay Bridge in Newport.
According to police reports of his alleged confession, Culver said that Ackerson was drunk and that he started hitting Ackerson "again and again" for annoying him, slamming his head against a tree and jumping on him until he wasn't sure whether Ackerson was dead or unconscious. He dragged the body onto the bridge with the two others and tossed him into the water, according to the police report of his confession.
Meister reinterviewed Calligan and Forsgren, getting them to allegedly admit that they were present when Troy snapped and beat Ackerson before they helped him carry the body onto the bridge in broad daylight. According to the police reports, Forsgren was fairly sure Ackerson was still alive when they tossed him off the bridge.
Meister said that Culver told police he had been haunted by the murder, and after meeting with Meister the nightmares became even worse and he had to get it off his chest.
"He said it was weighing on him since my interview with him, but it had really haunted him his entire life," Meister said.
Meister said that despite the confession, he soon realized the case was far from closed.
"All this time, poor Karen and her family are wondering 'He's confessed, why haven't you charged him?'" Meister said.
According to police, under Oregon law a person can't be convicted for a crime they confess to unless there is physical evidence to corroborate the confession.
In Oregon, Murder Confession Not Enough for Conviction
"Under Oregon Law, you can have somebody confess to something, but you can't convict them on that alone," Detective Quentin Bendell, who is now handling the Culver case, said.
Also Oregon law says that they have to use the sentencing guidelines from 1990 in Culver's trial, meaning he was looking at 10 years maximum.
"When they first came, I honestly believed the persons responsible would go to jail for the rest of their lives," Hull said. "But now two have testified to the grand jury and now they have immunity, and 10 years is the most Troy can get. But they think he might get three to five. I think that's where my anger is coming from, knowing these people are perfectly free to do whatever they want."
According to Bendell, the process has been frustrating, taking a year to try to put together after Culver's alleged confession.
Meister said they decided that with the slim chance of finding physical evidence after 20 years their best bet is having Forsgren and Calligan testify against Culver during the trial.
"Forsgren and Calligan were given immunity. It was a really tough choice for the district attorney. He lamented over this," Meister said.
Despite the bungled investigation in 1990, and two decades of heartache, Karen Hull said she now feels the police are now doing all they can for her and her son.
"Detective Meister is a good man, he is truly a good man," Hull said.
Culver was indicted by a grand jury last week, and is expected back in court in August. Meister hopes that anyone with information that could help lead the police to more evidence to call the Lincoln County Sheriff's Office, at (541) 265-0669.