Jan. 6 grand jury will speak with at least 1 more witness: Sources

At least one witness is expected to appear Thursday before the grand jury in Washington, D.C., investigating former President Donald Trump's efforts to overturn the 2020 election, sources tell ABC News.

Trump aide Will Russell previously appeared before the grand jury, so Thursday would be a return appearance.

Russell served in the Trump White House as a special assistant to the president and the deputy director of advance before moving to Florida to work as an aide to Trump after he left the White House.

Special counsel Jack Smith informed Trump on Sunday that he is a target in the election probe, suggesting that another indictment of the former president could be imminent.

As ABC has previously reported, multiple witnesses have appeared before the grand jury in recent weeks, including Trump's son-in-law and former White House senior adviser Jared Kushner.

Recent witnesses have been asked specifically about Trump's state of mind surrounding Jan. 6 and whether he was told and knew that he lost the election, sources have told ABC News.

Trump, who has denied all wrongdoing, has denounced Smith's probe as a political witch hunt.