A state grand jury in Winkler County, Tex., has indicted the sheriff, the county attorney and a hospital administrator for their roles in orchestrating the prosecution of two whistle-blowing nurses after they had reported allegations of malpractice.

The sheriff, Robert L. Roberts Jr., and county attorney, Scott M. Tidwell, each face six counts, including misuse of official information and retaliation, which are third-degree felonies. Stan Wiley, the administrator of Winkler County Memorial Hospital, in the dusty West Texas town of Kermit, was indicted on two counts of retaliation.

The case was investigated by the state attorney general after a jury last year acquitted one of the nurses of charges that she had misused official information by providing patient case numbers to the Texas Medical Board. In 2009, the nurse, Anne Mitchell, and a colleague, Vickilyn Galle, included the case numbers in an anonymous letter to the board about the practices of Dr. Rolando G. Arafiles Jr., who had recently joined the small hospital in Kermit.

The case against Ms. Galle was dropped before trial. Dr. Arafiles, who was arrested last month, faces four criminal counts, and has been charged civilly by the medical board with a variety of practice violations.