A Hardeman County grand jury has indicted Mary and Teresa Mayes, the mother and wife of Adam Mayes, but the details will not be released until Thursday's arraignment.
The pair is accused of helping Adam Mayes carry out his desperate plot to kidnap members of the Bain family in spring 2012, then kill two of them.
Teresa Mayes also faces murder charges for the killing of Jo Ann Bain and her oldest daughter, Adrienne.
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Grand jury proceedings are closed to the media, but FOX13 has learned the paperwork on the indictment was signed off Tuesday. Now, the pair will move through the legal process towards a trial.
According to Tennessee state law, the indictments can't be released until those accused have been served and properly arraigned.
Hardeman County District Attorney Mike Dunavant said a trial date and deadline for pre-trial motions is expected to be set Thursday. In previous hearings, explosive details surfaced about the role Adam's wife and mother played in his abduction plot.
According to Teresa, Adam poisoned Gary Bain, who survived, strangled Jo Ann, and smothered young Adrienne. During the killings, Teresa said she drove the youngest Bain girls in her SUV.
Adam Mayes killed himself May 10, 2012, after a search team located him with the kidnapped girls. The two girls were found safe.
Teresa said Adam's motivation behind the crimes was his love for 12-year-old Alexandria Bain. While Mary Mayes' defense says she was unaware about the kidnappings, the prosecution says she confined the two girls.
Teresa and Mary Mayes have been found competent to stand trial.
Their trials could start late this spring, possibly by May.
Fox13 has learned their trial could start late this spring.