An undocumented immigrant has been charged with first-degree murder in the presumed death of Mollie Tibbetts, an Iowa college student who went missing on July 18, officials said Tuesday. The body that officials believe is that of Tibbetts, 20, was found Tuesday. Authorities said surveillance video helped them determine a suspec, who led them to a cornfield where the woman’s remains were found. The suspect, Christian Rivera, 24, is an undocumented immigrant who authorities believe has been in the area for four to seven years. Authorities say the suspect followed Tibbetts on July 18 and then abducted her. An autopsy will be performed on Wednesday to determine when Tibbetts died and how. Tibbetts, a University of Iowa student, was last seen jogging on July 18 in the small community of Brooklyn, Iowa, about an hour east of Des Moines, according to the Poweshiek County Sheriff’s Office.