(Reuters) - A little-known former prosecutor with a doctorate in medieval history will play a central role on U.S. President Donald Trump’s legal team, as many top-tier lawyers shy away from representing him in a probe into Russia’s meddling in the 2016 election.

U.S. President Donald Trump waves as he walks on South Lawn of the White House in Washington, U.S., before his departure for the weekend in Palm Beach, Florida, March 23, 2018. REUTERS/Yuri Gripas

Andrew Ekonomou, 69, is one of a handful of lawyers assisting Jay Sekulow, the main attorney representing Trump in Special Counsel Robert Mueller’s investigation.

Sekulow told Reuters on Tuesday that after the departure of Washington attorney John Dowd from Trump’s personal legal team last week, Ekonomou will assume a more prominent role.

Ekonomou said he has been working with Sekulow on the Mueller probe since June.

The elevation comes at a crucial time in the Mueller probe, as Trump’s team is negotiating the terms under which the president himself may be interviewed. Sekulow is now the last man standing of a trio of personal lawyers hired last spring to assist Trump on the probe. Combative New York lawyer Marc Kasowitz exited the team last summer.

Sekulow said Ekonomou, who works under contract as an assistant district attorney in Brunswick, Georgia, was a “brilliant strategist” who has handled complex investigations for decades. Ekonomou assisted Sekulow in a famous case involving the religious group Jews for Jesus before the Supreme Court in the 1980s.

While Ekonomou has also worked on criminal matters, he has not handled cases as high-profile and complex as the Mueller probe.

In an interview, Ekonomou told Reuters that he “prosecutes a lot of murders for the D.A.”

When asked about his biggest cases of late, Ekonomou said, “That’s basically it. Nothing earthshaking.”

Ekonomou said he is up to the task of defending Trump, saying he has practiced law for more than four decades.

“I’ve been tested plenty of times,” Ekonomou said. “Just because you’re not a Beltway lawyer doesn’t mean you don’t know what you’re doing.”

Mueller is investigating Russian attempts to influence the 2016 U.S. election, and possible collusion by Trump aides. Russia has denied U.S. intelligence agencies’ conclusion that it meddled in the election, and Trump has said there was no collusion between his campaign and Moscow officials.

Trump has tried to tap top-tier lawyers to represent him but been repeatedly rebuffed, according to people familiar with the matter. For example, on Monday, Dan Webb, a former U.S. attorney in Illinois, said Trump had reached out to him and a Washington colleague, but business conflicts prevented them from representing the president.

Savannah Law School professor Andrew Wright, former associate counsel in the Obama White House, said it is unusual for a president to turn to lawyers like Ekonomou who are untested on the national scene and not part of the elite white-collar bar.

“He’s well past the A-team grab space,” Wright said.

Ekonomou said that since he began working with Sekulow, he has attended meetings with Mueller’s team. He said he brings more criminal experience to the table than Sekulow.

Ekonomou is a member of The Lambros Firm LLC, a boutique firm in Atlanta, which mostly handles civil and criminal racketeering cases for D.A.s around the state.

In the late 1970s and early ‘80s, Ekonomou spent several years in the U.S. Attorney’s office in Atlanta, where he was chief of the office’s criminal division and briefly served as acting U.S. attorney in 1982.

Since the Jews for Jesus case in the ‘80s with Sekulow, Ekonomou has done some work for the American Center for Law and Justice, a non-profit which advocates for religious and constitutional freedoms and is known for supporting Christian causes. Sekulow is the center’s chief counsel.

Following what he called a “mid-life crisis,” Ekonomou said he went back to school and got his doctorate in medieval history at Emory University in 2000. Ekonomou said he is the author of a book on Byzantine Rome and the Greek popes.

Drew Ashby, a trial lawyer who worked for Ekonomou between 2007 and 2010, said Ekonomou has a commanding presence that would likely serve him well when dealing with Trump.

“He is a force of nature,” Ashby said. “Andy has the kind of presence and the kind of mind that I would think would make Donald Trump listen.”