A Kansas grandpa is desperately searching for his four grandkids after their mom was brutally murdered and dumped in a shallow grave — allegedly by her husband, a self-proclaimed Mississippi cult leader called the “Silver Creek Messiah.” One of the last things La’Datra Williams, 26, told her grief-stricken dad, U.S. veteran Eddie Williams, on May 20 was she was “determined” to leave Charles Sims and his polygamous cult, which believes he’s a true vessel for the Holy Spirit and ordained by God almighty to fix the world’s problems. Sims is charged with first-degree murder for La’Datra’s killing. “I don’t know...