Washington CNN  — 

The Atlanta-area district attorney investigating Donald Trump’s efforts to overturn the 2020 election results in Georgia cast doubt Monday on the argument by the ex-President’s attorneys that he can’t be prosecuted for potential crimes committed during his time in office.

“Of course, I’ve given thought to if – that that may be raised as a legal issue,” Fulton County District Attorney Fani Willis said in an interview with CNN when asked about the argument his lawyers have previously made.

“I don’t think that that protection will prevent a prosecution if that becomes necessary in this state case,” she added.

Willis has been investigating whether Trump or his allies committed any crimes in their campaign to convince Georgia officials to find fraud and hand Trump a victory in the Peach State in 2020. The probe was launched last year following Trump’s call with Georgia Secretary of State Brad Raffensperger in which he pushed the Republican to “find” votes to overturn the election results.

“You and I have listened to that phone call. But also I have the benefit of also having talked to a lot of witnesses and probably having read more on this than most people would like to,” she said.

Willis told CNN on Monday that she’s not worried that the former President will try to delay her investigation, saying she plans “to use the power of the law” as grand jury proceedings in the case begin this spring.

“This is a criminal investigation. We’re not here playing a game,” Willis said. “I plan to use the power of the law. We are all citizens.”

“Mr. Trump, just as every other American citizen, is entitled to dignity. He’s entitled to be treated fairly. He will be treated fairly in this jurisdiction,” she added. “But I plan to do my job and my job is to make sure that we get the evidence that gives us the truth. I’m not concerned at all about games to delay this.”

Trump, whose litigious personality has long defined his political and business careers, has been known to retain legal teams that work hard to slow down cases against him, mucking up legal proceedings in hopes that they’ll eventually burn out.

Willis said she has already met twice with Trump’s legal team, most recently at the end of 2021 to inform them she was proceeding with the next steps in her investigation.

The comments from Willis come as her case against Trump picks up speed, with Fulton County Superior Court judges last month approving her request to seat a special grand jury to investigate Trump’s actions in office. The special grand jury, which will be seated starting May 2, does not have the authority to issue an indictment but it will allow Willis to seat a panel entirely focused on gathering evidence in the Trump investigation.

Willis said she plans to start issuing in subpoenas in May, although the bulk of them will likely come in the summer.

“Most of them will probably start to come in a heavier flow, for lack of a better word, in June and later months, but we will certainly start to do some in May,” she said. “The special-purpose grand jury not only has the power to subpoena witnesses to come to testify, but also other evidence that may be relevant, whether that’s emails, letters, phone calls, whatever you could imagine.”

Willis has said she needed such a grand jury to issue subpoenas to compel witnesses to testify and to gather additional evidence – a step toward pursuing possible criminal charges.

“I think the reason we needed a special-purpose grand jury was certainly we have tried to, for several months now, just call people in and ask them to speak to us. And some people are hesitant to do so – they were requesting a subpoena,” Willis said. “And so for my purposes, for the purposes of us being able to investigate, we needed a special-purpose grand jury.”

“Now will they push back further? Certainly some will, but I anticipate that we’ll be able to get them in and conduct a complete investigation.”

Willis’ sprawling probe has focused on not only Trump’s actions related to Georgia but also the activities of his allies, including former Trump attorney Rudy Giuliani, former White House chief of staff Mark Meadows and Republican Sen. Lindsey Graham of South Carolina.

“I imagine that we’re going to be issuing subpoenas to a lot of people, and that all of them are not going to welcome our invitation to come speak with us,” Willis said.

Willis said last month that her office has “received information indicating a reasonable probability that the State of Georgia’s administration of elections in 2020, including the State’s election of President of the United States, was subject to possible criminal disruptions,” according to her letter to the court requesting the special grand jury.

She told CNN that her team has identified more than 100 potential witnesses related to the investigation.

“When I sit down, I will have done everything that I know how to do to bring a fair and true picture. And so they’re welcome to their opinions,” Willis told CNN of her critics who believe she should speed up or narrow her probe.

“But while I sit here as the elected DA, we’re going to do things so that the American public can be confident we did everything we knew how to do to bring justice.”

CNN interviewed Willis on Monday at an Atlanta hotel after her office was temporarily locked down amid a potential security threat at the Fulton County Courthouse.

Willis, who has been the target of racists threats since she initiated her investigation, recently asked the FBI for assistance in assessing potential security deficiencies after Trump targeted her and other prosecutors at a recent rally and called on his supporters to protest.

“It’s not a joke. I take it very seriously,” she said when asked whether she was concerned that Trump’s comments could incite violence. “It was irresponsible. And that’s the best that I could say about it. It was irresponsible. If it wasn’t irresponsible, it was something much worse.”

This story has been updated with additional comments from Fulton County District Attorney Fani Willis.

CNN’s Paul LeBlanc contributed to this report.