The two sets of human remains found on Chad Daybell's property were eight-year old J.J. Vallow and 17-year-old Tylee Ryan, according to Larry Woodcock, grandfather of J.J. Vallow.
The children have been missing since September.
"Both children are no longer with us," Woodcock told the Post Register.
Two sets of children's remains were found buried on Chad Daybell's property by law enforcement on Tuesday.
Two charges were officially filed against Daybell on Wednesday morning. The charges involve the concealment of human remains "about to be produced, used and/or discovered as evidence in felony proceeding, inquiry and/or investigation authorized by law, with the intent to prevent it from being so produced, used and/or discovered."
The two concealment incidents were reported to have happened on or between Sept. 8, 2019 to June 9 and Sept. 22, 2019 to June 9, according to court documents.
The charges come the day after Daybell's Tuesday arrest.