On Monday, the Oklahoma State Bureau of Investigation held a press conference regarding two women who vanished late last month.

On Sunday, two bodies were discovered in rural Texas County, Oklahoma, amid a search for Veronica Butler, 27, and Jilian Kelley, 39. The pair vanished on March 30 while traveling to Adams’ home from Kansas to pick up Butler’s children. The vehicle they traveled in was abandoned near a highway outside Elkhart, Oklahoma.

During Monday’s press conference, authorities reiterated that evidence discovered inside and outside the vehicle led them to believe foul play was involved.

Officials said the evidence they uncovered while investigating Butler and Kelley’s disappearances led them to the two bodies — which have not been positively identified as of Monday. A cause of death is also pending.

READ: Two Bodies Found During Investigation Into Missing Mom And Preacher’s Wife

A day earlier, authorities confirmed four people were arrested in this case. Tifany Machel Adams, 54; Tad Bert Cullum, 43; Cole Earl Twombly, 50; and Cora Twombly, 44; have been charged with two counts each of first-degree murder, two counts of kidnapping, and one count of conspiracy to commit murder and were booked into the Texas County jail.

Adams is Butler’s former mother-in-law, and Cullum is her boyfriend.

Butler was reportedly going through a contentious custody battle for their two children with Adams’ son, her former husband. Ten days before the women’s disappearance, Butler had filed a request to see the children more frequently and was also reportedly seeking full custody.

Kelley, a pastor’s wife, was listed as one of four people who could supervise Butler’s visits with her children.

This story is developing.

*Additional reporting by KC Wildmoon

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[Featured image: Veronica Butler and Jilian Kelley/Oklahoma State Bureau of Investigation]