Special counsel continues to schedule witness interviews even as he moves closer to another possible Trump indictment

As anticipation builds for former President Donald Trump to be indicted for the third time this year, investigators in the special counsel's election interference probe are expected to speak with additional witnesses over the next several weeks, including at least one former Trump attorney.

Trump has been informed by special counsel Jack Smith that he is a target in the investigation into efforts by the former president and his allies to overturn the 2020 election - giving Trump the chance to testify or present evidence before a possible indictment Is brought. Such target letters are typically sent shortly before prosecutors move forward with charges.

At the same time, prosecutors have been in talks with at least two witnesses to schedule interviews with investigators that won't be completed for at least another month. Former New York City police commissioner Bernie Kerik, a Trump ally, is still in the process of scheduling his upcoming interview, and a former Trump lawyer plans to talk to investigators next month, sources familiar with the planned meetings told CNN.

It is unclear if prosecutors would wait until after their interviews have been completed before indicting Trump. It's also unclear how a possible case would be structured. For instance, Smith could bring a more discrete case first and then add on what are known as superseding indictments, or he could break up multiple defendants into separate cases.

On Thursday, Trump aide Will Russell testified to the grand jury investigating the 2020 election aftermath, including the January 6, 2021, attack on the US Capitol. A dispute over executive privilege during his testimony in the secret grand jury proceedings came to light when Russell's attorney, Stan Woodward, was late to a sentencing hearing for another client charged in the January 6 riot.

The grand jury hearing evidence in Smith's investigation met for more than 6 hours Thursday before concluding for the day shortly before 5 p.m. CNN spotted members of the grand jury leaving the courthouse Thursday afternoon, and prosecutors with Smith's office returned to their office in a separate building.

According to media reports, Woodward told the judge he was delayed by the dispute, prompting a kerfuffle when Judge Trevor McFadden ordered the special counsel prosecutors be brought to his courtroom to explain. An animated discussion at McFadden's bench ensued.

In the Mar-a-Lago classified documents case, Smith brought charges against Trump and his close aide Walt Nauta last month. But Smith's office has continued to investigate the handling of classified material after Trump's presidency ended, with inquiries of witnesses and grand jury activity.

In a sign that Smith's team could bring additional charges in the classified documents case, a Trump Organization employee who works at Mar-a-Lago recently received a target letter in connection with the ongoing investigation, according to a person familiar with the matter. The letter, first reported by ABC News, indicates prosecutors are exploring possible false statement charges related to the employee's grand jury testimony.

Trump also was indicted in late March by a Manhattan grand jury in connection with an alleged hush-money scheme.

In the election interference probe, investigators still appear to be gathering evidence as well. The special counsel's office is seeking Kerik's communications around the 2020 election, a source familiar with the matter told CNN. Kerik worked alongside former Trump attorney Rudy Giuliani in the weeks after the 2020 election to find any evidence of voter fraud that would swing the race for Trump.

When the January 6 congressional committee subpoenaed Kerik for documents, he provided a log of his communications that he said he was withholding due to attorney-client privilege. Those communications have never been disclosed publicly, as the committee did not challenge Kerik's privilege claims in court.

Timothy Parlatore, an attorney for Kerik, told CNN's Kaitlan Collins on "The Source" earlier this week that his client "hasn't done anything wrong."

"He was an investigator and everything he did was legal and appropriate," Parlatore, a former Trump attorney, said, adding: "We expect to sit down and explain that to the special counsel as well."