IOWA CITY, Iowa—The man on trial for the 2018 abduction and stabbing death of a University of Iowa student testified in his own defense Wednesday and claimed for the first time that two masked men were responsible for the crime but forced him to take part. In a surprise development, the defense called Cristhian Bahena Rivera to the witness stand at his first-degree murder trial. He admitted that his black car was the one seen on surveillance video circling Mollie Tibbetts while she was jogging in Brooklyn, Iowa, on July 18, 2018. He also acknowledged that she ended up in his car’s trunk and that he hid her body in a cornfield. But the farm worker presented a far different narrative about what happened than investigators and prosecutors have alleged, denying that he was responsible for stabbing her to death. Bahena Rivera said two armed men who were wearing black …