(RNS) The former office manager for atheist Madalyn Murray O'Hair has been indicted in the 1995 disappearance of O'Hair, her son, and granddaughter.

David R. Waters, 53, was indicted Tuesday [September 19] by a federal grand jury in Austin, Texas. Currently in prison serving a 60-year sentence on another charge, he is accused of extortion, kidnapping, and robbery resulting in the death of another person, the Associated Press reported.

O'Hair, her son Jon Garth Murray, and her granddaughter Robin Murray O'Hair disappeared five years ago with half a million dollars in gold coins. Authorities believe they were kidnapped, killed, and dismembered, but federal agents have failed to uncover any remains.

O'Hair, who was 77 when she disappeared, was involved in successful court cases in the 1960s that removed government-sponsored prayer and Bible-reading from U.S. public schools.

Waters was convicted of stealing from O'Hair's atheist organizations. He could face life in prison if he is convicted of the charges in Tuesday's indictment.

Waters' attorney was not immediately available for comment.