A preliminary autopsy for Mollie Tibbetts found that her death was a homicide caused by “multiple sharp force injuries,” according to a Thursday report from the Iowa State Medical Examiner. Tibbetts, a student at the University of Iowa, went missing after a jog on July 18. After a massive, weeks-long search, Cristhian Bahena Rivera led investigators to her body, which had been hidden in a corn field, police said. Rivera was arrested and charged with first-degree murder on Tuesday. In his police statement, Rivera, an undocumented immigrant, claimed he remembered following Tibbetts but “blacked out” at some point, police said.