(CNN) The weekslong search for Mollie Tibbetts, a 20-year-old Iowa student who disappeared while jogging, came to a grisly end Tuesday when a man guided investigators to a body in a cornfield. 
 
 While authorities have yet to confirm the body is Tibbetts, they arrested Cristhian Bahena Rivera, 24, on first-degree murder charges. 
 
 The discovery dashed the hopes of family and friends who had scoured Poweshiek and nearby counties as rewards grew to nearly $400,000. Tibbetts, officials said, is believed to have been abducted on July 18 as she went out for an evening jog. 
 
 Rivera, who's an undocumented immigrant, told them Monday that he saw and pursued her, getting out of his car and running beside Tibbetts. She warned him she would call police, officials told reporters Tuesday. 
 
 The suspect, who said he blacked out at some point, led authorities to the field Tuesday morning, they said. A body, dressed in Tibbetts' clothing, was covered in corn leaves. 
 
 It is unclear why Rivera killed Tibbetts, said Rick Rahn, special agent in charge at the Iowa Division of Criminal Investigation. 
 
 "I can't really speak to you about the motive," Rahn said. "I can just tell you it seems that he followed her and seemed to be drawn to her on that particular day and for whatever reason he chose to abduct her." 
 
 An autopsy to determine when and how the woman died is planned for Wednesday. 
 
 Authorities had been looking for Tibbetts about a month when they found home surveillance video that showed a car following a woman running. 
 
 After watching it for hours, investigators found clues that led them to Rivera. He didn't resist when authorities tried to detain him, Rahn said. 
 
 The suspect is an undocumented immigrant who authorities believe has been in the area for four to seven years, Rahn said. Charges were filed in district court in Poweshiek County and bail was set at $1 million. If convicted Rivera could get life in prison without parole. Iowa does not have the death penalty. 
 
 President Donald Trump referred to the case while speaking at a rally in Charleston, West Virginia. 
 
 "You heard about today with the illegal alien coming in very sadly from Mexico. And you saw what happened to that incredible beautiful young woman. Should have never happened. Illegally in our country," he said. "We've had a huge impact but the laws are so bad, the immigration laws are such a disgrace. We're getting it changed but we have to get more Republicans." 
 
 Police: Tibbetts told suspect she would call cops 
 
 Authorities said the suspect followed Tibbetts on July 18, the video recorded by a home surveillance system shows. 
 
 According to court documents, the suspect said in an interview that when he approached Tibbetts, she pulled out her cell phone and told Rivera she was going to "call the police" and that caused him to get angry. 
 
 He said he blacked out and woke up at an intersection in rural Poweshiek County, court documents say. 
 
 Rahn said the suspect told investigators he realized he had put the woman in the trunk of his car and when he took her out, he saw blood on the side of her head, the document says. He left the body in a cornfield and covered it with corn leaves, it adds. 
 
 Shawn Neudauer, a spokesman for Immigration and Customs Enforcement, said the agency on Tuesday sent a detainer request to local authorities for Rivera, who is from Mexico. That means ICE could take custody of Rivera if he was released from local custody. 
 
 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. 
 
 Other politicians weighed in on Tibbetts' death. 
 
 Gov. Kim Reynolds said she called Tibbetts' family. 
 
 "I spoke with Mollie's family and passed on the heartfelt condolences of a grieving state," Reynolds said. "I shared with them my hope that they can find comfort knowing that God does not leave us to suffer alone. Even in our darkest moments, He will comfort and heal our broken hearts." 
 
 She complained about a broken immigration system that allowed a "predator" to live in her state. 
 
 Sens. Joni Ernst and Chuck Grassley also sent condolences and called for action on illegal immigration. 
 
 "Too many Iowans have been lost at the hands of criminals who broke our immigration laws. We cannot allow these tragedies to continue," they said. 
 
 Vice President Mike Pence called Tibbetts an amazing woman. 
 
 "Heartbroken by the news about Mollie Tibbetts. Mollie was an amazing young woman and we are praying for her parents, brothers & friends in this time of unimaginable grief. ... We commend the swift action by local, state, & federal investigators working in Iowa in apprehending an illegal immigrant, who's now charged with first-degree murder. Now, justice will be served. We will never forget Mollie Tibbetts," he tweeted. 
 
 Extensive and lengthy search 
 
 Tibbetts 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. 
 
 The poster distributed asking for information about Mollie Tibbitts' disappearance. 
 
 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 at the University of Iowa and wanted to get a doctorate and write books, her father said. 
 
 Correction: An earlier version of this article incorrectly spelled the first name of the suspect. ||||| The body of missing college student Mollie Tibbetts was found Tuesday, her father and two sources told Fox News, bringing an end to an intensive search that lasted more than a month and captured national headlines. 
 
 Tibbetts' father, Rob Tibbetts, told Fox News the body found is that of his 20-year-old daughter, who vanished in mid-July. 
 
 A law enforcement source earlier told Fox News the body was found in Iowa, but more specific details about the location were not released. Iowa Department of Public Safety said a body was discovered in Poweshiek County. 
 
 Greg Willey, the vice president of Crime Stoppers of Central Iowa, also told the Associated Press the body found Tuesday is believed to be Tibbetts. 
 
 No arrests have been announced in connection with the Tibbetts case. A news conference was announced for 4 p.m. local time on Tuesday. 
 
 Tibbetts, a University of Iowa student, was reported missing after she failed to respond to messages from her boyfriend, Dalton Jack, and did not show up for work. She was last seen jogging around Brooklyn around 7:30 p.m. on July 18 and was staying with her boyfriend and working while home from school over the summer. She would have started her junior year of college this week. 
 
 MOLLIE TIBBETTS, UNIVERSITY OF IOWA STUDENT, MISSING: A TIMELINE OF EVENTS 
 
 Tibbetts' family pleaded for her safe return and had remained hopeful she would be found alive. Rob Tibbetts was returning home to the San Francisco area after spending weeks looking for his daughter, The Des Moines Register reported Sunday. 
 
 "The bottom line is somebody knows something," Rob Tibbetts previously told Fox News, adding Brooklyn is a small city and “you can’t do anything there without someone seeing it.” 
 
 For the last month, investigators followed “hundreds” of leads — interviewing hundreds of people and canvassing a nearby hog farm, cornfields and other properties for traces of the college student. Two items Tibbetts typically took with her — a Fitbit and cellphone — remained missing. 
 
 Investigators announced last week they were focusing the search on five locations in and around Brooklyn, which included a car wash just a block away from the city’s main commercial strip and a TA truck stop next to Interstate-80, which runs across the entirety of Iowa. 
 
 Brooklyn, a town of just 1,400 people, was shaken by Tibbetts' disappearance. Blake Jack, the brother of Tibbetts’ boyfriend, told Fox News on Aug. 8 there was no sign of a struggle at the Brooklyn home she was staying in at the time. 
 
 Dalton Jack, Tibbetts' boyfriend of two years, said he believed the doors of the home where his girlfriend last stayed had been left unlocked. 
 
 “It’s Brooklyn. You don’t lock your doors,” Jack told Fox News. “We lock our doors now. Every night.” 
 
 MOLLIE TIBBETTS, MISSING IOWA STUDENT, HAS ALWAYS RELIED ON PRAYER, DAD SAYS 
 
 Rob Tibbetts stayed optimistic to the end, theorizing his daughter must have been with someone she knew and would return home safe. 
 
 “It's totally speculation on my part, but I think Mollie is with someone that she knows, that is in over their head,” he told Fox News. “That there was some kind of misunderstanding about the nature of their relationship and at this point they don't know how to get out from under this.” 
 
 A reward of nearly $400,000 leading to information on Tibbetts' whereabouts will now become a reward for information leading to the capture of any suspects. 
 
 "Once they catch their breath, this will turn into a weapon going the other direction to catch the person who did it," Willey said. 
 
 Fox News' Matt Finn, Cristina Corbin, Greg Norman, Jennifer Earl and Elizabeth Zwirz and The Associated Press contributed to this report. ||||| CLOSE The Iowa Division of Criminal Investigation announces charges related to the Mollie Tibbetts case during a news conference in Montezuma, Iowa. Rodney White, rodwhite@dmreg.com 
 
 Cristhian Bahena Rivera (Photo: Special to the Register) 
 
 Editor's note: This story has been updated to reflect that Rivera's bond has been increased to $5 million. 
 
 MONTEZUMA, Ia. — An undocumented immigrant is in custody, charged with first-degree murder in the Mollie Tibbetts investigation, authorities said. 
 
 Cristhian Bahena Rivera, 24, has been in the area for four to seven years, officials said. Charges were filed in Poweshiek County court. He is being held on a $5 million cash bond. 
 
 Tibbetts was reported missing July 19, according to a criminal complaint. Shortly after her disappearance, investigators collected video footage from the east side of Brooklyn from the evening of July 18. 
 
 UPDATE: Man accused of murdering Tibbetts to be in court Wednesday 
 
 RELATED: University of Iowa students to honor Mollie Tibbetts Wednesday 
 
 The video showed Tibbetts running around Boundary and Middle streets outside of Brooklyn when a black Chevy Malibu drove in the area around 7:45 p.m. July 18. 
 
 The footage shows the vehicle, driven by Rivera, going back and forth in the area, according to the criminal complaint. 
 
 More Mollie Tibbetts coverage: 
 
 Officials pulled him in for questioning Monday, when he admitted to "making contact with a female running in Brooklyn" and that he pursued her to an area east of town in Poweshiek County, according to the criminal complaint. 
 
 Rivera told officials he exited his vehicle and started "running behind her and alongside her," according to the criminal complaint. Tibbetts then grabbed her phone and told him she was going to call the police, according to the criminal complaint. 
 
 He then told officials that he "got mad" and panicked and blocked his memory, which happens when "he gets very upset," according to the criminal complaint. 
 
 Investigators believe Tibbetts was abducted around the 1900 block of 385th Avenue. 
 
 Rivera told investigators he doesn't remember anything after that until he arrived at an intersection, according to the complaint. 
 
 Rivera then told officials that he made a U-turn, drove to an entrance of a field, pulled into a driveway and drove into a cornfield, according to the complaint. 
 
 He then realized he had earpieces in his lap, which made him realize that Tibbetts was in the trunk, according to the criminal complaint. Iowa Division of Criminal Investigation Assistant Director Mitch Mortvedt would not confirm whether Tibbetts was alive when Rivera allegedly placed her in the trunk. 
 
 Rivera told officials he pulled Tibbetts out of the trunk and found blood on the side of her head, according to the complaint. He then dragged Tibbetts to a secluded location in the cornfield, according to the complaint. 
 
 He told officials he then put her over his shoulder and took her 20 meters into the cornfield where he covered her with some cornstalks and left her. 
 
 Rivera was able to use his cell phone to determine the route he traveled from Brooklyn, according to the complaint. He later guided investigators to Tibbetts' location by memory, and law enforcement found a female body, according to the complaint. 
 
 The physical description matched what Rivera shared with officials and the clothing matched what Tibbetts was reportedly wearing on the night of her disappearance, according to the complaint. 
 
 
 
 
 
 CLOSE The Register's Shelby Fleig and Bryon Houlgrave report near the scene at 460th street on the latest news on the Mollie Tibbetts search. Bryon Houlgrave and Shelby Fleig, Des Moines Register 
 
 Mollie Tibbetts, 20, of Brooklyn, was last seen jogging on July 18, 2018 before her body was found in farm field one month later. (Photo: Jenny Fiebelkorn/Special to the Register) 
 
 Previous coverage: 
 
 This is a developing story. Check back for more updates. 
 
 Read or Share this story: https://dmreg.co/2w3BzZg
– Mollie Tibbetts' father confirmed the reports that emerged Tuesday morning: His daughter has been found dead. Rob Tibbetts made the confirmation to Fox News in advance of a 4pm local time news conference, at which time authorities revealed a first-degree murder charge has been filed in the case. The Des Moines Register reports the suspect is Cristhian Bahena Rivera, 24. He lives in rural Poweshiek County, where the body was found; Brooklyn, the town from which Tibbetts vanished, is in that county. Rivera has reportedly lived in the area for four to seven years and is an undocumented immigrant. CNN reports surveillance video helped authorities zero in on a suspect and that data from Tibbetts' Fitbit also provided clues. Officials say Rivera followed Tibbetts as she jogged and allegedly abducted her; they say he led them to a female body, which was in a cornfield and covered with cornstalks, per Special Agent Rick Rahn with the Iowa Division of Criminal Investigation. "For whatever reason he chose to abduct her," Rahn said. An autopsy is scheduled for Wednesday, and should reveal more on how and when she died, though the Register notes it could take as long as six weeks to get the results. The Des Moines Register reported the property where the body was found is a roughly 15-minute drive from Brooklyn. A medical examiner vehicle and SUVs were seen at the scene, and the Register reports a no-fly restriction has been put in place by the FAA over an area that encompasses "460th Avenue near North English River just southeast of Guernsey" through early Wednesday morning.