Federal prosecutors have begun to examine the actions and conduct of former President Donald Trump in the run-up to the Jan. 6, 2021 attack on the U.S. Capitol. This marks the biggest expansion of the Justice Department’s probe into the riot and it moves the investigation closer to the presidency.

On Tuesday, the Washington Post reported that federal prosecutors have been acquiring evidence from Trump’s former White House aides, as well as individuals close to former Vice President Mike Pence.

Pence figured prominently in Trump’s efforts to undermine the November 2020 presidential election that saw him defeated by now-President Joe Biden. During the riot, Pence refused to go along with a scheme concocted by Trump’s advisers to de-certify the results. Since his refusal, Pence has fallen out of favor with his former boss.

The investigation has so far gathered evidence in the form of electronic communications and witness testimonies from aides who served under Trump. Among the evidence seized were phone records that belonged to former White House Chief of Staff Mark Meadows, as well as those of lawyer John Eastman, who came up with the decertification plot.

Marc Short and Greg Jacob, two of Pence's top advisors, also were interviewed by investigators in recent weeks, according to the Wall Street Journal. The Journal reports that Short and Jacobs responded to a grand jury subpoena and spoke about a Jan. 4, 2021 White House meeting where Eastman pressed Pence to reject the election results in Trump's presence.

With the focus of DOJ now appearing to circle around Trump and his allies, the investigation has reached a critical stage. To date, the department has arrested nearly 800 individuals for their actions at the Capitol on Jan. 6, and it has charged the ring-leaders of right–wing extremist groups for their roles in trying to halt the election.

In an interview with NBC News, Attorney General Merrick Garland emphasized that “anyone” can be held accountable for their actions related to Jan. 6 when asked whether he supports criminally charging Trump.

"We pursue justice without fear or favor. We intend to hold everyone, anyone, who was criminally responsible for events surrounding Jan. 6, or any attempt to interfere with the lawful transition of power from one administration to another, accountable,” Garland told NBC News.

Garland previously stated that Trump's decision about whether to run for president again in 2024 would have no bearing on the DOJ's actions. No president in U.S. history has ever been charged for a crime.