THE only surviving child of Lori Vallow has revealed the last words he shared with his two younger siblings before they were allegedly murdered as part of a depraved Doomsday ritual.
A little over a week later, Tylee would vanish without a trace on September 8 following a family trip to Yellowstone National Park.
JJ then disappeared on Sept. 23, having last been seen sleeping in his uncle Alex's arms in Rexburg, Idaho.
The whereabouts of the two siblings would remain a mystery for nine months before their remains were tragically found buried in the backyard of Lori Vallow's newest husband, Chad Daybell, a grave digger-turned-Doomsday author, on June 9, 2020.
Throughout his agonizing wait for answers, Colby says he was regularly brought back to the final words he shared with Tylee and JJ, and how normal and happy the pair seemed in the days preceding their disappearances.
Tylee and JJ had visited Colby at work on August 30 to tell him they were moving with Lori out of Arizona in search of pastures new, but curiously they didn't know where they were heading.
They stopped by his work again the next day to say their goodbyes in person, before calling him that night before they went to bed.
"The conversation was just so normal," Colby said. "It was just a back and forth and then it was just over.
"I arranged plans to see them in a few weeks, so had I known I was never going to see them again there would've been a special goodbye, but I didn't know, so it was just a normal conversation.
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"It's crazy to think that was the last time I ever spoke to them," he added. "It's definitely hard [to think about]."
After his conversation with Tylee and JJ on August 31, Colby didn't have any direct contact with either of his two siblings, except for a few Venmo transactions and a couple of brief texts sent from Tylee's phone.
Each time he would try to ring Tylee the calls would go through to voicemail. This was out of character for his sister, Colby says, because the teen was always on her phone and if she ever missed a call, she'd immediately ring him back.
Growing increasingly concerned that something might be wrong, Colby reached out to his mom, who he claims acted shadily whenever he asked to speak with either of his siblings.
"It was pretty early on [after they disappeared], I reached out to my mom and she was being really shady about everything," Colby told The US Sun.
"The only thing she ever told me about Tylee is that she was super busy with school, and we only had that conversation once.
"I told her I was trying to contact them and call them, and that was right before she cut me off.
"I was just trying to pray and hope that everything was okay, but there was definitely a part of me that couldn't shake the fear that something might be wrong because everything just seemed and felt so odd."
"But at that moment I wasn't thinking, 'Oh, she's lying her head off, my siblings are gone,' because that just didn't seem possible, especially when you're talking to your mom, who you've known all your life."
However, Colby did start to worry the day before Thanksgiving when two detectives came to his front door asking him if he knew where Tylee and JJ were.
Colby once again called Lori who assured him she'd take care of things with the police.
Investigators with the Rexburg Police Department conducted a welfare check on Lori's Rexburg home looking for JJ on November 26.
She lied to the police, telling them JJ was staying with family members in Arizona.
Lori left town the following day and left no indication of where she was heading.
"It didn't dawn on me [that something was wrong] until she disappeared," Colby admitted.
"And then it was like, 'Okay, there's no way that everything is just normal' because [they] just disappeared to a place, and I don't know where, and now I can't talk to my siblings.
"And so I put her in her place, in a corner, asking her all these questions, and all I got back was just a bunch of lies."
Shortly after, Lori cut contact with Colby altogether.
The next time Colby would see his mother was after her arrest in Hawaii in February 2020 for ignoring a court order to produce her children to authorities.
"I asked her 100 times, 'what's going on?'" Colby said of the meeting. "
"And the only answer I ever got was, 'everything's going to be revealed soon.'
"So I just left. It was always a question mark - you couldn't get a straight answer.
"It was already hard enough to reach out and be the one to chase her down," he added. "But that's just kind of how it went."
HORROR PLOT REVEALED
Four months after meeting with his mother behind bars, the tragic truth of Lori's plot would be revealed following a search of Chad Daybell's Salem, Idaho home in June 2020.
In the backyard of the property, police found two sets of human remains buried in shallow graves that were soon confirmed to belong to Tylee and JJ.
Tylee's remains had been dismembered and burned, while JJ was found buried in his red pajamas and wrapped in plastic bags with tape covering his mouth, arms, and wrists.
Chad Daybell was taken into custody the same day and both he and Lori were later indicted by a grand jury on a number of charges related to the kids' deaths, including first-degree murder and conspiracy to commit murder.
Lori's devoted brother Alex Cox was also believed to be involved in their murders. However, he escaped charges after he died suddenly in December 2019 from what were believed to be "natural causes" spurred by high blood pressure and blood clots wedged in his lungs.
Investigators believe the two children were killed by Cox at the direction of Vallow and Daybell, who had allegedly become convinced to two children had been possessed by "dark spirits" and therefore needed to be purged.
For Colby, learning of the horrific way in which his siblings' lives ended was nothing short of devastating; harder still was coming to terms with the fact members of his own family were allegedly responsible.
Throughout the ordeal, right up until Tylee and JJ were found dead, Ryan said there was no doubt in his mind that his mom would never do anything to hurt her own children.
However, in the aftermath of his siblings' murders, Colby said he was consumed by dark thoughts and determined to enact revenge on his mom and Chad Daybell, believing them to be fully responsible.
"I was having the darkest thoughts about hurting them," Colby confessed. "[I was thinking] 'You want to hurt and kill my family? Then I'm going to kill you.'
"It was so, so dark. But that's how you feel when you want revenge."
Lori Vallow and Chad Daybell are both still awaiting trial for the murders of Tylee, JJ, and Daybell's late wife Tammy, who died in mysterious circumstances in October 2019.
Lori's trial was slated to begin this October but earlier this week a judge decided to delay proceedings by 90 days to coincide the trial with Chad Daybell's on January 9, 2023.
Vallow and Daybell have pleaded not guilty and could face the death penalty if they are convicted.
Despite Lori's claims of innocence, Colby says there is no doubt in his mind that she's "100%" responsible for all she stands accused of.
"My mom knew exactly what was going on," Colby said. "As a parent, you're responsible for your kids' safety, especially if they're minors. She was responsible for her kids. She was responsible for what happened.
"And I know she was a part of it," he claimed. "And that hurts a lot to say."
Colby said while he has no desire to have any sort of relationship with his mom moving forward, he admitted it's still difficult to hear she could potentially be sentenced to death.
"It's hard to hear that they would do that with my mom," he said, "but again, it's out of my hands and it always has been."
Colb typically refrains from following the coverage of his mom's trial now, again accepting that her fate is out of his hands.
Reliving the harrowing details of his siblings' deaths will also not change the fact they're no longer here, he said.
"I've given up the fact that no matter what happens, it's not going to change anything," Colby said.
"So I know they're in jail, I know they can't hurt anybody, and that's the best I can possibly ask for."
'THEY TOOK MY FAMILY'
Colby recently released a self-published book, , in which he discusses his faith and how turning to God helped him overcome the traumas of his childhood and beyond.
Where once he fixated on avenging his sibling's deaths, Colby said it was through his trust in a higher power that he was able to move past his overwhelming feelings of anger and resentment.
His path to enlightenment, he says, also allowed him to make the previously unimaginable step of forgiving his mother for her alleged crimes.
"They took my family away from me, they took them away from everybody else that loved them, and took them away from my kids having that relationship with them," Colby, a father of two, told The US Sun,
"But as time has gone by, I've had to say they took a lot from me, but whatever I've lost I know that God's grace has helped me not only regain but also come out of that dark place."
Colby added: "So it's not like I have everything I want back, and I've had to come to terms with the fact I'm just not going to get my family back, no matter what happens at trial, no matter if they were beaten up or not, or whatever the case was - it's just not going to change anything.
"It was a hefty, hefty price for them to take what they did ... but I had to let that go to move on with my life."