Update: Authorities have charged 24-year-old Cristhian Bahena Rivera with first degree murder in connection with Mollie Tibbetts' death. View the latest updates in the case here.

Mollie Tibbetts has been found dead, just over a month after she was reported missing, CBS News has learned. The 20-year-old University of Iowa student was last seen July 18, jogging near her home in the central Iowa town of Brooklyn.

Her family reported her missing the following day when she didn't show up for work. Her disappearance set off a massive investigation and weeks of fruitless searches.

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Police have scheduled a news conference for 5 p.m. ET on Tuesday to provide an update on the latest developments. The body was discovered in Poweshiek County, the Iowa Division of Criminal Investigation said in a news release. So far, no details have been released about what the cause of death might be.

Investigators received information early Tuesday which led them to a field in the area, a law enforcement source told CBS News. There is heavy police activity in rural Poweshiek County, just south of Interstate 80 near Iowa Highway 21, CBS affiliate KCCI-TV reports.

Last week, authorities said they were focusing their investigation on five areas in and near Tibbetts' hometown. Those locations reportedly included her boyfriend's home in Brooklyn, a car wash, a truck stop, a farm more than three miles from downtown Brooklyn, and another farm more than six miles away. Police asked anyone who was in those areas on July 18 to report anything suspicious they may have seen.

In an interview earlier this month, Mollie Tibbetts' father said he believed his daughter may have left willingly with someone she knew. "I think someone went to the house that Mollie knew or that Mollie trusted and that she left with them willingly," Robert Tibbetts told CBS News. "Now they're in over their head and they don't know what to do."

He said if he could talk to his daughter, he would tell her to "hang on."

"We're gonna come get you," he said. "Everybody's looking."

More than $385,000 was raised for a reward for Mollie's safe return. Greg Willey of Crime Stoppers of Central Iowa told the Associated Press the fund will now likely be used for any information that helps police catch whoever is responsible for her death.

Tibbett's photo was posted across most of Brooklyn, sometimes two posters were placed on a single storefront. Residents placed signs in their yards and wore T-shirts that displayed her image along with a phone number to alert authorities.

Earlier this month, her parents told CBS News they were touched by the support displayed by their community. "I think it struck a chord with people that, you know, 'this could be happening to me right now, to my family,'" her mother, Laura Calderwood said.

"I think it's because people see in Mollie their own daughters, their own girlfriend, their own sister," Robert Tibbetts said.

Tibbetts would have started her junior year at the University of Iowa this week.

Adriana Diaz and Pat Milton contributed to this report. The Associated Press also contributed reporting.