Bonnie Clark Haldeman, the mother of dead cult leader David Koresh, was found dead from a stabbing wound in Chandler, Texas on Saturday.  Halderman’s sister, Beverly Clark, is under police custody for the killing.

Bonnie Clark Halderman, 60, was found Friday afternoon at the home of her sister, Beverly Clark, 54, in a rural area near Chandler, about 175 miles north of Houston in East Texas, Henderson County Sheriff Ray Nutt said.

“It’s still under investigation and we really don’t know what the motive was or what caused this to happen,” Nutt said Saturday.

The sheriff said someone made a 911 call summoning deputies to the home Friday.

David Koresh was the leader of the Branch Davidian cult that had a 51-day standoff with Bureau of Alcohol, Firearms and Tobacco that resulted in the death of Koresh and eighty of his followers when the building they were in burned to the ground.