Holtz had been shot in the head.
Neither Gerald nor Alice Uden had an attorney. Messages left Monday with the Christian County Sheriff's Department seeking interviews with them were not returned.
Danny Herd, a neighbor of Gerald and Alice Uden, said the couple and several of their adult children had lived on about 60 acres of land in the Chadwick area, near the Mark Twain National Forest, for at least 15 years.
He said the Udens worked as long-haul truckers and were rarely home. The couple's rig was towed off the property Monday morning, he said.
Jim Salter and Alan Scher Zagier in St. Louis, Mo., and Bob Moen in Cheyenne contributed to this report.
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