Four people involved in an anti-government group they called God’s Misfits have been arrested on murder and kidnapping charges in the disappearance of two Kansas women who last month were likely targeted over a custody dispute, the authorities said.

Two bodies were recovered as part of the investigation, but they have not yet been identified, the authorities said on Monday.

Tifany M. Adams, 54; her boyfriend, Tad B. Cullum, 43; Cora G. Twombly, 44; and her husband, Cole E. Twombly, 50, were arrested on Saturday and each was charged with two counts of first-degree murder, two counts of kidnapping and one count of conspiracy to commit murder in the first degree. Court documents did not include contact information for lawyers for any of the four people. They were being held without bond at Texas County Jail, in Guymon, Okla., The Oklahoman reported.

On March 30, Veronica Butler, 27, and Jilian Kelley, 39, were traveling from Hugoton, Kan., to Oklahoma. They were reported missing after Ms. Butler didn’t arrive at a birthday party later that day. Members of Ms. Butler’s family found her vehicle abandoned that same day in a rural area of Texas County, Okla., which is about 270 miles northwest of Oklahoma City.

Ms. Twombly’s 16-year-old daughter, who is not named in the charging documents, said that her mother had told her that she and the three other people arrested were involved in Ms. Butler’s and Ms. Kelley’s deaths.

The daughter said that all four charged were part of what the authorities said they called God’s Misfits, an anti-government group with a religious affiliation, and that there had also been an attempt to kill Ms. Butler in February.

Investigators later found that the members of God’s Misfits held weekly meetings in their homes. There was a fifth person attending those meetings who was not arrested. Little else was known about the group’s origins or membership, the authorities said.

Hunter McKee, a spokesman for the Oklahoma State Bureau of Investigation, said at a news conference on Monday that there was no chance that the women were still alive, though two bodies recovered during the investigation into their disappearance had not yet been identified by the state medical examiner.

“This case was tragic,” Mr. McKee said. “You have two people who are dead and four people that committed an absolutely brutal crime.”

Ms. Adams is the grandmother of Ms. Butler’s two children, and the affidavit for her arrest said that there had been a “problematic” custody battle between them. The children’s father, Wrangler Rickman, is Ms. Adams’s son and was in a rehabilitation facility at the time of the disappearance. Ms. Adams had custody of the children.

Mr. McKee said that the children were safe, but he would not say where they were.

The custody battle began in February 2019, the affidavit said. Ms. Butler’s attorney told investigators that she was likely to be granted more time with her children at a hearing in April.

On March 30, Ms. Butler was scheduled to meet Ms. Adams and pick up her children for a visit that would be supervised by Ms. Kelley as ordered by the court, according to the affidavit. Ms. Kelley, a pastor’s wife, was one of three people approved by the court to supervise Ms. Butler’s weekly visits with her children. Ms. Butler planned to bring her daughter to a birthday party, but when she did not arrive, her family started to look for her. Family members contacted the police after finding her abandoned vehicle.

There was blood on the road near the vehicle and Ms. Butler’s glasses were found on the road near a broken hammer, the affidavit said. A pistol magazine was found inside Ms. Kelley’s purse, but no pistol was found.

Ms. Adams told investigators that Ms. Butler had called before the meeting and said that she was not going to be able to make it. The investigation found that three prepaid cellphones that Ms. Adams purchased in February had been in the area where Ms. Butler’s car was found when she disappeared.

Two of the three prepaid phones purchased by Ms. Adams were found to have been at a private property that was about 8.5 miles from where Ms. Butler’s car was found, according to tracking data, the affidavit said. Ms. Adams’s boyfriend, Mr. Cullum, rents a pasture on that property for cattle grazing.

At the property, investigators found “that a hole had been dug and filled back in and covered with hay,” the affidavit said.

Investigators interviewed family members of the four suspects, including at least two who indicated that their relatives were involved in the women’s disappearance.