pdq, I take it you are opposed to the movement she was part of that resulted in the Supreme Court decision to stop Bible reading and recitation of prayers in public schools?

Truthorfiction.com has some information on some of the urban legends about her.

She was a founder of the American Atheists organization. O'Hair, her son Jon Garth Murray and the granddaughter she had adopted, Robin Murray O'Hair, were killed, dismembered and dumped on a private, 5-000 acre Texas ranch in 1995. The bones indicated three sets of human remains, and all had their legs cut off. The remains and the ground around the bones were charred, indicating a fire at the scene.

At the time, investigators also expected to find partial remains of Danny Fry, who was a suspect in the family's disappearance. His body was found in the Dallas area, but the head and hands had been severed.

David Roland Waters (who worked at the organization as "office manager") and an accomplice named Gary Karr were found guilty of their kidnapping and murders. In 1995, Waters pled guilty to stealing $54,000 from the Murray O'Hairs. He was put on probation and ordered to pay restitution. He had previous convictions on murder, battery, and forgery. He (Waters) even appeared on the television show America's Most Wanted, during which he denied knowing anything about the whereabouts of the atheists.

All the intrigue was apparently about the most valuable asset of the American Atheist organization, their library valued at between $1-$3 million, and the atheist publication "The Truth Seeker". Murray O'Hair apparently intended to disappear with the library assets, to avoid paying out a settlement for a lawsuit brought against the organization by the estate of the publish of "The Truth Seeker".