On Tuesday, police in Iowa arrested Cristhian Rivera, 24, charging him with first-degree murder for the death of University of Iowa student Mollie Tibbetts. Tibbetts, 20, disappeared while jogging on the evening of July 16, sparking a search involving the FBI and state and local investigators. Rivera led police to a body in a cornfield on Tuesday morning, according to court documents, and police believe the body is Tibbetts'. Rivera's motive is unclear, Rick Rahn, special agent in charge at the Iowa Division of Criminal Investigation, said at a news conference, but the suspect says he got mad and blacked out when Tibbetts threatened to call the police as he was following her on her run. Rivera is an undocumented Mexican national who has lived in Iowa for at least four years. Tibbetts would have been a sophomore this fall. You can learn more below. Peter Weber

Update 3:25 p.m. ET: Rivera's lawyer filed a court document Wednesday morning that disputed the suspect's immigration status. Attorney Allen Richards said the "government is incorrectly promoting the idea that Rivera is not in Iowa legally," the Des Moines Register reported. In fact, Rivera was working legally at an Iowa farm owned by the brother of Craig Lang, a prominent Iowa Republican. Read more at the Des Moines Register.

Some Republicans are beginning to worry they may lose a Senate seat to Democrats — in Mississippi.

Voters in the state are set to participate in a runoff election on Nov. 27, as neither Republican Sen. Cindy Hyde-Smith nor Democratic challenger Mike Espy captured a majority in the midterm election. But Hyde-Smith has been mired in controversy in recent weeks, first for a remark about a "public hanging" and then for saying that making it difficult for liberals to vote sounded like a "great idea." Her campaign dismissed the former comment as an exaggeration and the latter as a joke.

After these gaffes, Republicans are reportedly "nervous" that Hyde-Smith, who was appointed to her seat earlier this year and is now running for a full term, could cost them a Senate seat, with one top party member in the state telling Talking Points Memo that the race "is definitely tighter than what it should be." Talking Points Memo also reports that some private polls show the race has tightened and Hyde-Smith is only up by a few points.

Democrats are engaging in a last-minute push to get out the vote, Politico reports, hoping to increase turnout, specifically among black voters. President Trump appears not to be taking Hyde-Smith's win for granted, as he plans to travel to the state for two rallies on Monday. Trump won Mississippi by 17 points in 2016.

If Espy, the former agriculture secretary in the Clinton administration, were to actually defeat Hyde-Smith, he would be the first Democratic Senator to represent the state in nearly three decades, and the first black Senator from Mississippi since Reconstruction. The candidates will square off in a debate Tuesday night. One Republican told Talking Points Memo, "It's all about whether we can get through the debate without saying anything that makes it worse." Brendan Morrow

The main U.S. stock indexes plunged on Monday, weighed down by negative news about Apple and Facebook.

Facebook shares fell by nearly 6 percent in continued fallout from a New York Times report on the social network's aggressive response to criticism over its handling of fake news and other efforts to influence public opinion. Apple shares fell by 5 percent after a Wall Street Journal report that disappointing sales had prompted the company to cut orders for its latest iPhones.Shares of Google-parent Alphabet also fell by 4 percent.

The Dow Jones Industrial Average closed down by 1.6 percent, while the tech-heavy Nasdaq Composite lost 3 percent and the S&P 500 dropped by 1.7 percent. Stock futures fell further early Tuesday, Fox Business reports, suggesting more tech-fueled selling. Harold Maass

President Trump's immigration agenda has just suffered a major legal setback — again.

Judge Jon S. Tigar of the U.S. District Court in San Francisco late Monday issued a temporary restraining order blocking the Trump administration from denying the asylum claims of immigrants who cross the U.S. border with Mexico illegally, The Washington Post reports. Trump had rolled out his plan days after the midterms in response to the caravan of migrants making their way to the United States from Central America.

The judge said Monday that Trump does not have the authority to "rewrite the immigration laws to impose a condition that Congress has expressly forbidden." Whether a person arrives at a legal point of entry "should bear little, if any, weight in the asylum process," he said, as is reflected under current law. Additionally, the judge said the immigrants would be put at "increased risk of violence and other harms at the border" if Trump's ban went into effect, CNN reports.

This is just the latest legal setback the Trump administration has faced when it comes to immigration; an appeals court earlier this month also blocked Trump from ending DACA, the program that gives protections to undocumented immigrants who came to the United States as children.

Judge Tigar's temporary restraining order will expire on December 19, at which point another hearing will take place and a permanent order could be issued. Brendan Morrow

The United States is contemplating placing Venezuela on its list of state sponsors of terrorism, a person familiar with the matter told Reuters on Monday.

In September, Sen. Marco Rubio (R-Fla.) and two other GOP senators sent Secretary of State Mike Pompeo a letter stating that Venezuela has ties to the Revolutionary Armed Forces of Colombia (FARC) and the Lebanese militant group Hezbollah, but did not offer any concrete evidence. They asked for Venezuela to be added to the list, which has four countries on it: North Korea, Iran, Syria, and Sudan.

A U.S. official told Reuters those countries have "repeatedly provided support for acts of international terrorism," and for Venezuela to be added to the list, there has to be sufficient proof. Venezuela is experiencing food and medicine shortages and hyperinflation, and if the country ends up on the list, it could limit economic assistance from the United States. Venezuelan President Nicolas Maduro has said he is the victim of an "economic war" with the U.S. Catherine Garcia

There are lots of words you could use to describe President Trump, but Seth Meyers thinks there's one that everyone can admit fits him best: weird.

"He is a weird man," Meyers said on Monday's Late Night. "Just a flag hugging, umbrella ditching, can't do a normal handshake kind of weirdo." One of the more bizarre things Trump does is make up an outlandish lie about another country, which can easily be fact checked and proven untrue. In February 2017, for example, Trump claimed there was an attack in Sweden, when there was not. The "deeply weird president" was at it again on Saturday in California, when he started talking about taking care of the "floors of the forest" like they do in Finland.

Trump declared that the president of Finland told him in his "forest nation" they "spend a lot of time on raking and cleaning" and in turn, they don't deal with things like devastating fires. The president of Finland later clarified he did not say that people in his country are going around raking 24/7, and Meyers is certain that "we're a week away from the president of Romania calling a press conference to say, 'I did not tell President Trump that vampires are real.'" Trump, Meyers concludes, has to "concoct fantastical lies" because they "reinforce his deluded worldview, and they're easier to swallow than reality." Watch the video below. Catherine Garcia

On Monday, the White House announced it had restored CNN reporter Jim Acosta's hard press pass, following a legal battle.

At the same time, White House Press Secretary Sarah Huckabee Sanders and Deputy Chief of Staff Bill Shine announced new guidelines for journalists covering press conferences. They are only allowed to ask one question, with any follow-ups answered at the discretion of President Trump or the White House official holding the press conference. When a journalist is done asking their question, they must also hand over the microphone. Anyone violating those rules could have their press pass suspended or revoked.

The White House announced it was revoking Acosta's pass on Nov. 7 following a testy exchange with Trump, and his refusal to give the microphone to an aide. CNN took the matter to court, and a judge temporarily restored Acosta's press pass on Friday. Catherine Garcia