Trump co-defendant Michael Roman subpoenaed, Kenneth Chesebro interviewed in Arizona 2020 election probe: Sources

Michael Roman, a former Trump campaign aide who was indicted alongside the former president in the Georgia election interference case, has been subpoenaed as part of a separate probe in Arizona investigating efforts to overturn the 2020 election results in that state, according to a source familiar with the matter.

The subpoena, which has not been previously reported, comes as part of an ongoing investigation by Arizona Attorney General Kris Mayes, whose office previously confirmed to ABC News she was investigating the so-called "alternate elector" plot in the state.

"We will announce something in the relatively near future," Mayes said recently of the investigation.

Attorney Kenneth Chesebro, who is accused of helping devise the Trump campaign's fake elector plan, sat for an interview with investigators in Arizona in recent weeks, sources also told ABC News. Chesebro was indicted in the Georgia investigation and took a deal with prosecutors, changing his plea to guilty to a single felony charge and agreeing to cooperate.

A source said Chesebro was not subpoenaed in Arizona and sat for the interview voluntarily.

In a statement, a spokesperson for Trump's campaign called the investigation a "Witch-Hunt" and repeated the baseless claim it is being run by President Joe Biden.

"President Trump is dominating Crooked Joe Biden and his Democrat allies know it, so they continue to ramp up their ongoing Witch-Hunts, further abusing the power of their offices to interfere in the presidential election," Steven Cheung said in a statement. "The American People will not fall for the Biden-directed Hoaxes and will hold Crooked Joe and his comrades to account this fall."

An attorney for Roman and a spokesperson for the Arizona attorney general's office declined to comment to ABC News.

ABC News previously obtained a Dec. 6, 2020, memo authored by Chesebro, that laid out a plan for "alternate" electors to meet, vote, and send in their certificates to be counted in a proposal that prosecutors said was designed to "mimic as best as possible the actions of the legitimate Biden electors, and that on January 6, the Vice President [would] open and count the fraudulent votes, setting up a fake controversy that would derail the proper certification of Biden as president-elect."

Witnesses in the Arizona probe have been questioned about the ties between local Republican officials and the 2020 Trump campaign regarding the origin of the fake elector plan and the numerous lawsuits looking to overturn the election in the state, sources said. Some witnesses have been asked directly by investigators about the involvement of senior advisers on the Trump campaign, said sources.

Roman was previously indicted in Georgia in August alongside Trump and 17 others over allegations that the group attempted to overturn that state's election results. He pleaded not guilty to the seven counts he faces, which include charges relating to his alleged efforts to help coordinate and appoint alternate slates of electors.

The indictment alleges Roman was involved in that effort in multiple states.

"I need a tracker for the electors," Roman allegedly wrote in a December, 2020 email, according to the indictment, in which he allegedly instructed individuals associated with the Trump campaign to update a spreadsheet listing presidential elector nominees in Georgia, Arizona, Michigan, and other battleground states.

Prosecutors in multiple other states have also brought charges over the alleged effort to submit alternate slates of electors. In June, prosecutors in Michigan filed felony charges against 16 Republicans over their alleged efforts to replace Michigan's electoral votes for Joe Biden with electoral votes for then-President Donald Trump, with nine of them subsequently pleading not guilty.

In December, the Nevada attorney general indicted six so-called alternate electors for falsely portraying themselves as Nevada's duly-elected presidential electors. Earlier this month, Politico reported the office had issued a number of grand jury subpoenas.

In November, Mayes told CNN that the Arizona investigation was "robust."

"We're going to make sure that we do it on our timetable, applying the resources that it requires to make sure that justice is done, for not only Arizonans, but for the entire country," she said.