News Cristhian Bahena Rivera found guilty of first-degree murder in 2018 killing of Mollie Tibbetts May 28, 2021 William Morris, Des Moines Register Comments Off on Cristhian Bahena Rivera found guilty of first-degree murder in 2018 killing of Mollie Tibbetts Mollie Tibbetts went missing after going for a run on July 18, 2018. The University of Iowa student's body was found in a cornfield a month later.