Natalia Veselnitskaya is at the center of the political firestorm around the meeting in 2016 that Democrats are claiming as proof of collusion between the Russian government and the Trump campaign.

The Russian lawyer was characterized as an agent of the Russian government's effort to defeat then-Democratic nominee Hillary Clinton, though she denies the connection.

Now questions are arising about how she was in the country in the first place to attend that meeting.

According to a report from the Daily Beast, Veselnitskaya didn't appear to have visa authorization to enter the country when she did in 2016.

The U.S. Attorney’s Office of the Southern District of New York said that Veselnitskaya had been granted an "immigration parole" in 2015, but it expired in early 2016 and wasn't renewed.

The State Department would not confirm or deny whether Veselnitskaya applied again for a visa in 2016, let alone if a visa was granted. A spokesperson told The Daily Beast the State Department could not comment due to privacy considerations. Veselnitskaya also did not respond to requests for comment.

Senate Judiciary Committee Chairman Sen. Chuck Grassley (R-Iowa) is demanding answers from the State Department on the issue. In a letter sent to Secretary of State Rex Tillerson, he wrote, "It is unclear how [Veselnitskaya] was still in the country for that meeting despite being denied a visa beforehand and her parole purportedly expiring on January 7, 2016."

"This raises serious questions about whether the Obama administration authorized her to remain in the country, and if so, why?" he asked.

Some have speculated that the Obama administration had something to do with allowing her in the country, fueling a conspiracy theory that the entire meeting was orchestrated to set up Donald Trump Jr.