Warning: Graphic details.
Police have used mobile phone information from the now-deceased uncle of two missing children to find their bodies on a rural property, according to court documents.
Police found the remains of 17-year-old Tylee Ryan and her brother, 7-year-old Joshua "JJ" Vallow, on June 9 in the US state of Idaho after months of searching.
They hadn't been seen since September and investigators said the children's mother Lori Vallow Daybell and her husband Chad Daybell lied to police about the children's whereabouts.
Court documents made public late Friday reveal that the FBI tracked the cellphone of Alex Cox, Vallow's brother and JJ and Tylee's uncle.
The FBI tracked Cox's phone to the Daybell's property four times during the month of September, 2019.
According to court documents, Cox's phone pinged on September 6, 9, 23 and 25 at the location where the remains were found.
On September 9 - just 14 minutes after Cox leaves Daybell's property - documents reveal Daybell texted his then-wife Tammy Daybel.
"Well, I've had an interesting morning!", the text reads.
"I felt I should burn all of the limb debris by the fire pit before it got too soaked by the coming storms. While I did so, I spotted a big raccoon along the fence.
"I hurried and got my gun, and he was still walking along. I got close enough that one shot did the trick. He is now in our pet cemetery. Fun times!"
The pet cemetery mentioned happens to be the same area where the FBI pinged Cox's phone, according to the document.
The documents also revealed how police discovered the children's' remains.
When police served a search warrant at the property on June 9, 2020, they reported finding multiple sites of interest.
"The first site of interest was located on the north side of the pond near the north edge of the property. This site corresponded with the two GPS pings from Alex Cox's phone on September 23, 2019," the document reads.
Investigators exhumed an area of disturbed ground and located human remains, later confirmed to be JJ, wrapped in plastic and bound with duct tape.
They reportedly identified a second set of remains in the area where Daybell's neighbours had reported seeing the bonfires.
"Methodically, the dirt in this area was searched and several other items of interest were found including other bones, charred tissue and charred bones," it reads.
"[Boise State University associate professor of anthropology] Cheryl Anderson indicated these additional bones, both charred and uncharred and tissue found were human remains."
Chad Daybell has pleaded not guilty to destroying evidence. Lori Daybell has been in jail since February, charged with child abandonment and obstructing the investigation.
Both Daybells are being held on US$1 million bond, and both are scheduled for preliminary hearings next month.
The complex case spans several states and began when Lori Daybell's brother shot and killed her estranged husband, Charles Vallow, in suburban Phoenix last summer in what he asserted was self-defence.
Vallow was seeking a divorce, saying his estranged wife believed she had become a god-like figure who was responsible for ushering in the biblical end times.
Her brother, Alex Cox, then died in December of an apparent blood clot in his lung.
Shortly after Vallow's death, the mum and the children moved to Idaho, where Chad Daybell lived.
He ran a small publishing company, putting out fiction books he wrote about apocalyptic scenarios loosely based on the theology of The Church of Jesus Christ of Latter-day Saints.