Family members confirm the children's remains found on Chad Daybell's property belong to seven-year-old JJ Vallow and 17-year-old Tylee Ryan.
JJ's grandparents, Kay and Larry Woodcock, made the heartbreaking confirmation.
The two kids had been missing since September last year.
Woodcock told the Post Register:
"Both children are no longer with us."
The announcement came hours after the FBI discovered the remains buried in the backyard of Chad Daybell's home in rural Idaho.
Mysterious Disappearance of JJ Vallow and Tylee Ryan
Authorities have been looking for JJ since September last year when school officials and family members reported him missing.
His older sister, Tylee, went missing around the same time.
But the thing that made the case stand out was the apparent lack of concern from their mother, Lori Vallow.
And when JJ's biological grandmother asked about the whereabouts of the children, Lori wouldn't give a straight answer.
The Woodcocks Asked Rexburg Police to Check on The Kids
When officers questioned Lori Daybell, she and Chad Daybell lied about the children's whereabouts.
And when investigators returned the next day to follow up, the Daybells were gone.
While the couple slipped away to Hawaii, investigators pursued, eventually arresting them. And a judge ordered Lori Daybell to bring the children to officials to prove they were safe.
But Lori refused, and prosecutors charged her with child abandonment and other crimes, then extradited her to Idaho.
The case drew worldwide attention after investigators uncovered increasingly strange circumstances surrounding Lori Daybell and her new husband, Chad Daybell.
Some of the circumstances include mysterious deaths of their former spouses, rumors of doomsday cult-like beliefs, and 'sudden marriage.'
Two Sets of Human Remains on Daybell's Property
On June 9, that agony reverberated through the hearts of everyone following JJ's and Tylee's disappearance.
While the FBI worked with local officials to search Chad's Daybell's property, they found human remains. The officers later confirmed the remains belonged to children.
Authorities questioned Chad and charged him with 'two felony counts of concealment and destruction of evidence.'
Though relatives say those children's remains are Tylee and JJ, they're still waiting for answers.
In a joint statement, the extended family wrote:
"We are filled with unfathomable sadness that these two bright stars were stolen from us and only hoped that they died without pain or suffering."
"We ask that you respect our family's privacy while we grieve since we have only just been told of the loss of our loved ones and need time to process."
It's unclear whether prosecutors are preparing to file new charges against the couple following the bodies' recovery.
Our deepest condolences go to all the families affected by this unthinkable tragedy.