(CNN) -- 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, said Rick Rahn, special agent in charge at the Iowa Division of Criminal Investigation. An autopsy is planned for Wednesday.
Authorities said surveillance video helped them determine a suspect. He led them to a cornfield where the woman's remains were found.
The suspect, Cristhian Bahena Rivera, 24, is an undocumented immigrant who authorities believe has been in the area for four to seven years, Rahn said. Charges were filed in the district court in Poweshiek County.
Authorities said the suspect followed Tibbetts on July 18 and then abducted her .
The autopsy will determine when Tibbetts died and how.
Rahn said Tibbetts' digital footprint, which included data from a fitness tracker known as a Fitbit, played a role in solving the case.
Tibbetts' father, Rob Tibbetts, when reached earlier Tuesday, had no comment.
Mollie 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.
Before she went missing, Tibbetts' brother dropped her off at her boyfriend's house so she could dog-sit, HLN reported. Her family reported her missing after she did not show up for work the next day.
Investigators launched an extensive search for Tibbetts across the area, including in ponds, fields and from the air.
Rahn said last week that authorities had received more than 1,500 tips and conducted more than 500 interviews in the case.
Tibbetts was studying psychology and wanted to get a doctorate and write books, her father said.