▶ Watch Video: Trump faces possible indictment in Jan. 6 probe

Washington — Federal investigators working for special counsel Jack Smith questioned at least two witnesses in recent days about former President Donald Trump’s conduct after the 2020 presidential election, according to multiple sources familiar with the matter. 

Smith’s office sent Trump a target letter Sunday, Trump announced earlier this week and multiple sources confirmed to CBS News. Such letters indicate prosecutors could be nearing a decision on whether to indict Trump in the election-related investigation. Still, investigators have been continuing their work in the days after sending Trump the letter, questioning witnesses about the former president and his conduct. 

Letters informing individuals that they are targets of an investigation are not mandatory in federal prosecutions, but investigators send them in certain situations to offer the individuals the opportunity to testify. 

On Thursday, Trump aide Will Russell appeared before a federal grand jury in Washington, according to two people familiar with the matter. A close Trump adviser, Russell was with the former president for part of the day on Jan. 6, 2021, and moved to Florida to continue working for Trump after his presidency. Russell had already testified on at least one other occasion before the grand jury. 

Without naming Russell, his attorney, Stanley Woodward, told a federal judge in another matter on Thursday in open court that his client was being asked questions not previously posed that dealt with matters of executive privilege. Woodward represents both Russell and a Jan. 6 Capitol breach defendant — one-time State Department employee Federico Klein, whose trial was also set for Thursday afternoon — and was late to Klein’s proceedings because of the grand jury testimony. 

Irritated by the delay, Judge Trevor McFadden, who was overseeing the Klein trial, pressed Woodward about his tardiness and said he waived any grand jury secrecy rules to allow Woodward to provide an explanation. Then, taking unusual and dramatic judicial prerogative, McFadden summoned special counsel prosecutors, including top Jan. 6 investigator Thomas Windom, into his courtroom to explain the matter at the bench, out of public earshot. 

Woodward did not identify his client by name in court and declined to comment further, regarding both CBS News reporting of Russell’s testimony and the matter in McFadden’s court. 

Smith’s office also declined to comment.

The special counsel’s team is building a sprawling case focused on how Trump acted in the days after the election and whether the former president criminally conspired to block the certification of Joe Biden’s victory in Congress, people familiar with the investigation told CBS News. Simultaneously, the special counsel is probing whether, as part of a scheme, Trump allegedly pressured Republicans in states to send fake slates of electors saying he won and urged officials and governors to take fraudulent actions to make it seem as though there were a basis for overturning Mr. Biden’s victory in their states. 

In recent days, Smith’s office reached out to former Arizona Gov. Doug Ducey, a Republican, according to a spokesperson for Ducey. “He’s been contacted. He’s been responsive, and just as he’s done since the election, he will do the right thing,” said the spokesperson, Daniel Scarpinato.

State officials in other battleground states, including Georgia’s Republican secretary of state, Brad Raffensperger, have spoken with investigators in recent months. 

The special counsel’s team could continue questioning witnesses and has been scheduling potential interviews for next month, according to sources. Former New York City Police Commissioner Bernard Kerik is in talks to meet with prosecutors soon, according to a person familiar with the matter. Kerik was among those assisting Trump attorney Rudy Giuliani’s unsuccessful efforts to find evidence of voter fraud after the election. CNN first reported Kerik’s possible interview. 

Other key witness testimony could occur in the coming weeks, too, according to people familiar with the matter. 

Trump has consistently denied all wrongdoing and has blasted Smith’s probe as politically-motivated. 

The special counsel charged Trump last month with 37 federal counts for his alleged mishandling of classified documents, to which he has pleaded not guilty. A trial date is set in Florida for May 2024, just as the 2024 presidential primary season is coming  to a close.