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A grandmother accused of killing two Kansas women amid a child custody battle searched "taser pain level" and other phrases that give insight into the women's horrific deaths, court documents reveal. 

Grandmother Tifany Machel Adams, 54, her boyfriend, Tad Bert Cullum, and married couple Cole and Cora Twombly all face two counts of first-degree murder, two counts of kidnapping and one count of conspiracy to commit murder in the deaths of 27-year-old mother Veronica Butler and visitation supervisor Jilian Kelley, a 38-year-old preacher's wife who was also a mother. 

The four belonged to a religiously affiliated anti-government group called "God's Misfits," Fox News Digital previously reported

Their motive, investigators say, was to get custody of Butler's two children. Wrangler Rickman, Adams' son, had custody of the children but was confirmed to be in an Oklahoma rehab facility when the women disappeared. Butler was allowed supervised visitation with her children every Saturday and was likely to be granted unsupervised visitation during an upcoming hearing, per court documents. 

Butler and Kelley were last seen alive on March 30 as they set off from Hugoton, Kansas, to a court-supervised visit with Butler's two children in Oklahoma. 

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Veronica Butler and Jillian Kelley vanish in Oklahoma

Veronica Butler, left, and Jilian Kelley were last seen March 30 while driving to pick up children, police say. (Oklahoma Highway Patrol)

When the pair never brought Butler's daughter to a birthday party as planned, Butler's family set off to look for the two women. 

They found Butler's car on the border between Kansas and Oklahoma with "evidence in and around the vehicle that indicated a severe injury," including blood on the road and Butler's glasses on the ground near a broken hammer.

A pistol magazine was found in Kelley's purse at the scene, investigators wrote, but the pistol was nowhere to be found, according to a probable cause affidavit obtained by Fox News Digital.

Interviews with the Twombly's 16-year-old and a review of Adams' phone and data from three burner phones led investigators to find the women's bodies on April 14 in a cow pasture leased by Cullum, court documents show.

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Missing persons suspect Tifany Adams

Tifany Machel Adams, 54, is reportedly the grandmother of Veronica Butler's children. She had searched "taser pain level" and purchased five tasers in the days before the two women went missing, court documents show. (Oklahoma State Bureau of Investigation - Authorized Page/Facebook)

Adams told police that Butler and Rickman's children were staying the night with family friends on March 29 and that Butler had canceled her visitation with the children on the morning of March 30. But Butler's phone records indicated that although she did call Adams, she was in the process of picking up Kelley for the visit. Kelley was Butler's preferred supervisor for visitations, investigators wrote.

Rickman's grandmother, Debi Knox-Davis, reported to police that the father of the children told her their family wouldn't have to worry about their custody battle with Butler for much longer, per court documents. He told her Adams "knew the path the judge walked to work," she told police, and that they planned to "take out Veronica at drop off (sic)." 

The Oklahoma State Bureau of Investigation (OSBI) obtained a warrant to search Adams' phone on April 1. Searches performed on the device allegedly included "taser pain level," gun shops, prepaid cellular phones and "how to get someone out of [your] house."

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Missing persons suspect Tad Cullum

Tad Callum, 43, is reportedly the boyfriend of 54-year-old Tifany Adams, who is the grandmother of Veronica Butler's children. (Oklahoma State Bureau of Investigation - Authorized Page/Facebook)

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A search of local gun shops later showed that Adams had purchased five stun guns on March 23.

On April 3, the Twombly couple's daughter reportedly told police that she was told her parents, Adams and Cullum were responsible for Butler and Kelley's deaths. Adams had provided the other three with burner phones, she said, so they could communicate discreetly about their plans.

Before the women were last seen on March 30, the 16-year-old reportedly said she'd overheard conversations between the four suspects about how "Butler [was] not protecting her children from her brother ... in reference to a sexual abuse allegation." 

Cora and Cody Twombly

Pictured are Cody and Cora Twombly, whose 16-year-old daughter's statement to police helped seal their arrests in the murders of Veronica Butler and Jilian Kelley. (Texas County Sheriff's Department)

The 16-year-old said her parents told her they would "not have to worry about [Butler] again" and that the two may have been placed in a well, per court documents.

"[The 16-year-old] asked why [Kelley] had to die and was told by Cora that [Kelley] wasn't innocent either, as she had supported Butler," investigators wrote.

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The group's plan was initially to "throw an anvil through Butler's windshield while driving, making it look like an accident because anvils regularly fall off work vehicles," Cora allegedly told the 16-year-old.

The minor reportedly named a fifth party who was involved in planning the women's deaths but who has yet to be arrested. 

OSBI investigators found records that Adams had purchased the three prepaid cellphones. Tracing the previous locations of the phones led detectives to "fresh dirt work" covered with hay, where the women's bodies were found, according to authorities.

Although the women's bodies and causes of death are pending a medical examiner's report, OSBI said, there is "no chance" Butler and Kelley are still alive.

"This case is tragic," OSBI spokesperson Hunter McKee told KFDA. "You have two people who are dead and four people who committed an absolutely brutal crime."