Kay and Larry Woodcock are offering a $20,000 reward for anyone who can help them find their 7-year-old grandson, Joshua "JJ" Vallow, and his sister, 17-year-old Tylee Ryan. The siblings were last seen in Rexburg, Idaho, on September 23. The Woodcocks knew something was wrong when they hadn't heard from the grandson, who usually FaceTimed them regularly. Police say the children's mother, Lori Daybell, has refused to help find them. The FBI is involved in investigating their disappearance.