RELATED: Nancy Guthrie abduction: The full timelineOn Friday, the Pima County Sheriff's Department released details from two ransom notes received by Tucson media in the days after the abduction. The second note, sent on Feb. 6 to the Guthrie family, said Nancy Guthrie died and "is buried in nature now," according to the sheriff's department. In response to an inquiry from ABC News, the sheriff's department said Tuesday that "investigators have seen a slight increase in tips since the two ransom notes were released," adding that "all tips have been followed up on." Savannah Guthrie again pleaded for help in an Instagram post Saturday, writing, "We need someone to come forward." Perhaps they are afraid to come forward."