Prosecutors in Idaho want to join the criminal cases against Chad Daybell and his wife, Lori Vallow, the mother of two children whose remains were found at Daybell's home.

Special prosecutor Rob Wood and the state of Idaho moved to join the cases, reasoning both defendants participated in the same series of acts, according to court documents obtained by KSAZ-TV.

"Charges against defendant & the co-defendant allege they participated in same act or series of acts & conspired to commit the alleged act or series of acts," the motion reads.

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Idaho prosecutors are asking a judge to join the cases against Lori Vallow and her husband Chad Daybell. Both are criminally charged in connection with the discovery of the remains of her two children on Daybel's Idaho property. 

Idaho prosecutors are asking a judge to join the cases against Lori Vallow and her husband Chad Daybell. Both are criminally charged in connection with the discovery of the remains of her two children on Daybel's Idaho property.  (The Associated Press )

Daybell is charged with two counts each of concealment of evidence and conspiracy to conceal evidence connected to the discovery of 7-year-old Joshua "JJ" Vallow and 17-year-old Tylee Ryan on his Idaho property in June. Vallow also is charged with the same crimes.

They are not charged in the children's deaths. The children were last seen in September 2019, igniting a bizarre case that has spanned multiple states - Idaho, Arizona and Hawaii - and raised questions about the deaths of Daybell's and Vallow's former spouses.

Authorities said the couple lied to investigators about the children's whereabouts and were not cooperative during the search.

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Daybell's attorney is asking a judge to throw out the charges against him. In a motion filed last week, defense attorney John Prior said the charges against his client were not supported by evidence and that they are unfairly duplicative of one another.

"The prosecution made assertions in his Complaint and Information that are vague and overly broad," Prior wrote, according to KTVB-TV in Boise, Idaho. "Those assertions violate Defendant’s U.S. and Idaho Constitutional rights to be fairly notified and appraised of when, how, and what he is accused of doing."

Vallow and Daybell married in November, weeks after their previous spouses died and the kids were last seen. Investigators in Arizona previously told Fox News they planned to file charges against Vallow in connection with the shooting death of Charles Vallow, her former husband.

He was shot by Alex Cox, Lori Vallow's brother, in July 2019 following an altercation at a suburban Phoenix home. Vallow reportedly was seeking a divorce from his wife.

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Cox claimed he killed his brother-in-law in self-defense; Cox died in December of natural causes. After her estranged husband's death, Lori Vallow moved to Idaho and eventually married Daybell, a "doomsday prepper," in November.

Daybell's deceased wife, Tammy Daybell, died in October a few weeks before he and Vallow married in Hawaii. Tammy Daybell's body was exhumed in December, but autopsy results have not been released.