IOWA CITY, Iowa—A prosecutor rejected defense claims Thursday that the 2018 killing of University of Iowa student Mollie Tibbetts could be connected to sex trafficking and other abductions that happened in the rural area where she disappeared while out for a run. A 21-year-old man’s alleged confession that he helped kill Tibbetts after she was kidnapped and held at a house used for sex trafficking wasn’t credible, Assistant Attorney General Scott Brown said during a hearing on what had been the day 27-year-old Cristhian Behena Rivera was due to be sentenced for her death. “No evidence supports it. None. Zero,” Brown said. He told the court that information about the 21-year-old from two witnesses who came forward late in Behena Rivera’s trial independently of one another was inconsistent with Bahena Rivera’s own courtroom account of what happened. In a court filing before Thursday’s hearing, he argued there should be “no …