President Donald Trump had almost certainly never heard the name Aaron Zebley before the announcement that the former FBI agent was joining the special counsel investigation into ties between Trump’s campaign and Russia. But to those who have followed the arc of the bureau during the past twenty years, Zebley’s is a name that underscores just how far-reaching and dogged—and potentially long—the probe will likely be.

Just ask Steve Gaudin’s ex-girlfriend.

She wasn’t at all happy when Zebley, her boyfriend’s FBI partner, called at 3 one morning in August, 1999. Despite all of Gaudin’s international travel, chasing al Qaeda long before the terrorist group was a household name, he and his girlfriend had managed to settle down in New York City and carve out a life together in between his overseas terrorist hunts. The couple was even looking forward to an imminent, albeit brief, summer vacation.

View more

But then came the call from Zebley.

“I’ve found Ali Mandela,” Zebley said, excitedly. Mandela, the fugitive terrorist suspected of helping execute the previous year’s bombings of US embassies in East Africa, appeared to still be on the continent, he told Gaudin. Somewhere in South Africa. They had to leave immediately.

Angry at yet another sleepless night—and vacation—ruined by the bureau’s demands, Gaudin’s girlfriend gave him some advice: Don’t bother coming back.

But that was just the way it was for the elite agents on one of the FBI’s most storied squads. Nothing could come between them and their search for justice.

The details of that trip—and the subsequent capture of one of America’s most wanted terrorists by Zebley and Gaudin—help illuminate the makeup of the special counsel team that former FBI director Robert Mueller is assembling. It’s a team that contains some of the nation’s top investigators and leading experts on seemingly every aspect of the potential investigation—from specific crimes like money laundering and campaign finance violations to understanding how to navigate both sprawling globe-spanning cases and the complex local dynamics of Washington power politics.

Meet Mueller's Roster

As Mueller begins investigating Russia’s interference in last year’s election and its possible links to Donald Trump’s campaign, he is quietly recruiting lawyers and staff to the team. And in recent days, Trump associates have stepped up criticism of Mueller and his team—including a report, quickly rejected by the White House, that Trump is considering firing Mueller before he even gets started.

Tuesday morning on Good Morning America, Newt Gingrich blasted Mueller and his still-forming team. “These are bad people,” Newt Gingrich told George Stephanopoulos. “I’m very dubious of the team.”

But that criticism flies in the face of widespread, bipartisan acclaim for the team. In fact, just a day earlier, on the same program, former Whitewater prosecutor Ken Starr praised Mueller at length. “I don’t think there’s a legitimate concern about Bob Mueller,” Starr said, explaining that the former FBI director was “honest as the day is long.”

From the list of hires, it’s clear, in fact, that Mueller is recruiting perhaps the most high-powered and experienced team of investigators ever assembled by the Justice Department. His team began with three lawyers who also quickly left WilmerHale, the law firm where Mueller has also worked since he left the FBI in 2013—Zebley, James Quarles III, and Jeannie Rhee.

The rapid recruitment of Quarles attracted immediate attention: A famed litigator who was an assistant special prosecutor for the Watergate investigation, Quarles specialized in campaign finance research for the Watergate task force, which surely will be an area of focus for Mueller’s investigation. (The FBI has been serving subpoenas regarding the finances of campaign adviser Michael Flynn and campaign chairman Paul Manafort, both of whom have retroactively registered as foreign agents, admitting that they were paid by foreign governments during the period when they were also advising Trump.) In more recent years, Quarles has risen through the law firm’s ranks to run its DC office, and is an experienced manager. In granting him the firm’s top recognition in 2007, one of his colleagues said that Quarles “represents precisely the values that should define us culturally and reputationally: He is an excellent lawyer, he is an extraordinary hard worker, he is the ultimate team player, and he treats everyone with respect and collegiality.”

It’s a team that’s not just a paper office tiger but one with deep experience investigating crime around the world.

More recently, Mueller has recruited Andrew Weissmann, his one-time general counsel at the FBI and a long-time adviser who once led the Justice Department’s fraud unit. In the early 2000s, Weissmann also oversaw the Enron Task Force, the storied Justice Department unit that investigated the complex machinations of the failed energy giant. (The task force’s team of prosecutors was so well-respected that they went on to dominate the Justice Department’s top ranks for the better part of a decade, including former officials like White House homeland security adviser Lisa Monaco, White House counsel Kathy Ruemmler, assistant attorney general Leslie Caldwell, and acting assistant attorney general Matthew Friedrich.)

Then Mueller added Michael Dreeben, who has worked for years in the Justice Department’s solicitor general’s office, which argues the government’s cases before the Supreme Court. “Dreeben is 1 of the top legal & appellate minds at DOJ in modern times,” tweeted Preet Bharara, the former top Manhattan federal prosecutor. Walter Dellinger, an accomplished law professor at Duke and former acting solicitor general, went one step further, telling The Washington Post, “Michael is the most brilliant and most knowledgeable federal criminal lawyer in America—period.” Writing on the Lawfare blog, Paul Rosenzweig recalled watching Deeban argue a Supreme Court case—one of more than a hundred he’s done—without a single note, and also concluded, “He is quite possibly the best criminal appellate lawyer in America (at least on the government's side). That Mueller has sought his assistance attests both to the seriousness of his effort and the depth of the intellectual bench he is building.”

Also, while the Special Counsel’s office has yet to make any formal announcements about Mueller’s team, it appears he has recruited an experienced Justice Department trial attorney, Lisa Page, a little-known figure outside the halls of Main Justice but one whose résumé boasts intriguing hints about where Mueller’s Russia investigation might lead. Page has deep experience with money laundering and organized crime cases, including investigations where she’s partnered with an FBI task force in Budapest, Hungary, that focuses on eastern European organized crime. That Budapest task force helped put together the still-unfolding money laundering case against Ukrainian oligarch Dmitry Firtash, a one-time business partner of Manafort.

But despite the other more high-profile names, it’s the career of Zebley, a dogged FBI agent turned prosecutor turned confidant, that perhaps best points to how Mueller intends to run his new investigation: With absolute tenacity and strong central leadership from Mueller himself. It’s a team that’s not just a paper office tiger but one with deep experience investigating crime around the world.

Tenacious Z

Zebley, who has worked alongside Mueller since their departure from the Hoover Building in 2013, attended the College of William & Mary—James Comey’s alma mater—and went on to the University of Virginia’s law school, a prime feeder school for federal prosecutors, including Mueller himself. Zebley then started with the FBI on I-49, one of its most storied squads and part of the small group of agents in New York who were chasing Osama bin Laden and al Qaeda before September 11th.

I-49 was tasked with investigating the twin bombings of the US embassies in Kenya and Tanzania in 1998, known within the Bureau as KENBOM and TANBOM; each agent on the squad was assigned a specific suspect. Zebley, one of the squad’s youngest agents, pursued Ali Mandela, a man whose nickname referred to his resemblance to a younger Nelson Mandela.

When Gaudin and Zebley got to South Africa in the summer of 1999, they almost immediately realized the news wasn’t good. The suspect they assumed to be Ali Mandela in fact wasn’t him. Nevertheless, Gaudin and Zebley found themselves in a small conference room in Cape Town with the FBI’s South African liaison and officers from the country’s immigration and refugee asylum service, who insisted that the visiting FBI guests at least review some immigration records while they were there.

The South Africans pulled out boxes stuffed with immigration cards and dumped them on the table. Gaudin and Zebley groaned and agreed to peruse the cards before their evening flight back to the States. Miraculously, the second card Gaudin picked up to examine bore fruit.

“Zeb, where do I know this name from? Who is Zahran Nasser Maulid?” Gaudin asked, holding up the picture with the name written across the top.

“That’s KKM!” Zebley almost shouted.

“Who the fuck is KKM?” a South African official asked. “That’s not your guy.”

“What’s going on here?” the FBI’s liaison asked, also confused.

Gaudin and Zebley pulled the South African aside—they realized they were onto something big, and couldn’t risk a leak. “Who do you trust? This is important.”

Just months earlier, the agents had discovered that Khalfan Khamis Mohamed—the man the FBI suspected of assembling the bomb used in Tanzania—had used the name Maulid as an alias to get a Tanzanian passport. The South African police officer shooed a few people from the room and assembled five officers, four men and one woman. “These people, these are the best. What’s going on? Who’s KKM? I thought we were looking for Ali Mandela.”

“No, you don’t understand,” Gaudin said, holding up the picture. “This guy is Khalfan Khamis Mohamed. There’s already an indictment for him—he’s one of the bombers. If we can get him, there’s a $5 million​ reward on his head.”

Gaudin called back to the New York Field Office and told his bosses that the two agents had stumbled upon one of the country’s most wanted terrorists. And they even had a plan to arrest him.

The South African immigration services explained that every 42 days, like clockwork, Mohamed had to come back to the refugee office to get his visa renewed. As long as he wasn’t scared off, there was no reason to think he wouldn’t walk right into the FBI’s arms if they were patient. A small team of backup FBI agents was dispatched to South Africa, and they settled in to wait.

Working undercover, Zebley and Gaudin waited at the immigration facility, with Gaudin posing as a South African colonel. Refugees seeking asylum queued each morning, and in typical bureaucratic fashion, not everyone got his or her visa stamped. Latecomers were turned away, forced to return some other day or risk arrest if the authorities found that they’d overstayed their visas. Tensions ran high in the queue, with the crowd becoming more frantic as the day wore on and hopes of getting visas successfully renewed dwindled. One afternoon, Zebley and Gaudin watched in horror as the authorities wheeled out a fire hose and blasted the crowd to keep it under control.

The two agents realized that, given the line’s chaos, the only practical thing to do was somehow to get to the applicants early: They had to streamline the refugee office’s visa renewal process if they hoped to capture KKM. The team hatched a plan. Gaudin, dressed in his full colonel’s uniform, complete with epaulets and medals, and looking vaguely like a character from a Gilbert and Sullivan operetta, went out each morning with a basket to collect the refugees’ immigration cards. Then all the cards were brought inside and stamped. The refugees waited peacefully outside for their documents, which were returned in the afternoon. This meant not only that the FBI had a first, calm look at the documents but also that the South Africans suddenly had a much more efficient mechanism for processing immigration claims.

Their system worked smoothly—​a little too smoothly, actually. The crowds got larger as word spread in the refugee community that a new policy meant everyone was getting a stamp. No more wasted days! The head of refugee services, who had no idea that an American FBI team was operating undercover in his agency, asked to meet this innovative new colonel who had so streamlined and revolutionized his agency’s process. Gaudin, nervous that he’d blow the whole operation, was summoned and thanked for his contribution. “We haven’t had to use the fire hose all week,” the head of refugee services announced, without any idea of Gaudin’s real identity.

The weeks ticked by as KKM’s 42​-day deadline approached. Finally, the last day arrived: October 5, 1999. The small team of FBI agents and South African immigration officers stationed themselves strategically around the building. Zebley and other agents positioned themselves in cars around the corner.

Gaudin went out with his basket. After weeks of the dulling routine, he searched each refugee’s face with renewed enthusiasm, his energy mounting as he worked his way down the line. KKM was here somewhere. Yet Gaudin made it to the end of the morning line without any luck.

Then came a shout from his South African partner at the front door of the office: “Steve, the boss wants to see you.”

“Not now. I’m busy.”

“No, Steve, the boss really needs you. You need to come right now.”

Walking inside, dejected, Gaudin boarded the elevator and found himself standing just inches away from Khalfan Khamis Mohamed. Sully, the South African officer, had seen the terrorist suspect walk up to the end of the line and, unaware of the new policy that ensured everyone a stamp, turn away after mentally calculating that he was unlikely to reach the front of the line that day. The officer had approached him and, thinking quickly, quietly told Mohamed that for some money he would take him to the head of the line and get him a stamp. The Tanzanian bomb maker happily forked over a few hundred rand—after all, getting the stamp that day meant he wouldn’t have to miss another day at the Burger World franchise where he had worked since the attack. The South African officer then led him up to the front and sent his partner to grab the FBI agent.

As the elevator ascended, Gaudin cracked a joke about how he was probably in trouble and was being summoned to the boss’s office. The group disembarked on the top floor, still laughing. The two South African police officers went first, KKM second, and Gaudin brought up the rear, the police acting as casually as they could. Ten feet passed. Twenty feet passed. Gaudin, last in the line, was getting nervous. The building was cavernous; if KKM got spooked and escaped down a hallway or made it to a stairwell, it was possible that they would never see him again. Finally Gaudin’s anxiety overcame him. He broke into a full sprint and slammed into the bomber from behind, his arms encircling KKM and pinning his arms. The two men dropped hard, like a linebacker sacking a quarterback in a high school football game.

Gaudin handcuffed the dazed and confused suspect and rolled him over, growling, “FBI. Don’t even bother telling me you’re not KKM.” Zebley and the other agents pounded up the stairs and into the hallway, with South African officers close behind. The agents hustled the terrorist down to the basement, into a waiting car, and off to the airport for the long flight to the United States. He was convicted and sentenced to life without parole in 2001.

By that point, Zebley had thought he was done with counterterrorism. He transferred off the counterterrorism squad on September 10, 2001, heading to work criminal cases.

The transfer lasted exactly one day.

Mueller’s Right-Hand Man

Within days of the devastating attack, the brand-new FBI director—Robert Mueller, who had started only on September 4th—decided to centralize the investigation into the September 11th attacks at the Bureau’s headquarters in Washington, an all but unprecedented move to lead an operational case from the Hoover Building itself.

While Mueller didn’t personally lead the PENTTBOM case, the decision to centralize it at headquarters—where he could see it, touch it, and have investigators be instantly available for questions—marked a significant departure from the FBI’s tradition of allowing field offices wide independence on investigations. It also underscored Mueller’s understanding that high-profile, politically sensitive investigations required a tactile, hands-on approach. It is a model that Mueller will likely carry forward into his role as special counsel in the Russia investigation, ensuring that he’s always personally involved even as he delegates threads of the case to experienced investigators like Quarles and Zebley, who was one of the first agents the FBI assigned to the PENTTBOM case in Washington.

On that PENTTBOM case, Zebley was so steeped in the intricacies of the 9/11 attacks that the Justice Department turned to him as the courtroom witness in 2006 to testify that, if Zacarias Moussaoui—the so-called 20th hijacker who was arrested in August 2001—cooperated and allowed his belongings to be searched sooner, the FBI could have likely unraveled the 9/11 plot before it was executed.

Zebley told the courtroom and jurors that the FBI could have used information in Moussaoui’s possession, including phone records and money transfers, to identify and draw links between 11 of the 19 hijackers who participated in the 9/11 attacks. One of the defense attorneys asked Zebley if the FBI could have used that information to stop the attacks.

“We’ll never know, right?” the defense attorney asked.

“Correct,” Zebley replied.

In the years that followed, Zebley rose to become a special counselor to Mueller himself, and after Mueller’s ten-year term as FBI director had been extended for an additional two years by a special act of Congress, Zebley took over as his chief of staff. He also later worked in the Justice Department’s National Security Division, which oversees counterterrorism and counterintelligence cases, like the one into Russia’s election meddling.

In every instance, their investigations have been textbook examples of sober, patient, thorough exploration.

Zebley followed Mueller to WilmerHale in 2014, where Mueller has built a steady practice as the respected voice beyond reproach that organizations turn to when they need sensitive internal investigations. He served as Mueller’s right hand during major investigations, including one that Mueller led into the NFL’s handling of the Ray Rice domestic violence incident in 2014, and ones into more recent crises like Takata’s deadly airbags and VW’s emissions scandal.

In every instance, their investigations have been textbook examples of sober, patient, thorough exploration. Zebley helped lead the way through the political minefield of the NFL investigation, even as it ultimately and unexpectedly concluded—after a fruitless search of emails, telephone calls, and in-person interviews—that the NFL headquarters had never received a video of Rice’s assault. In the straightforward language that is Mueller’s trademark, the investigation was scathing in its conclusion that the NFL erred in its handling: “The NFL should have done more with the information it had,” the so-called “Mueller report” concluded, “and should have taken additional steps to obtain all available information about the February 15 incident.”

Now, though, Zebley and Mueller—as well as Quarles and the rest of the investigators—will face perhaps their biggest challenge yet, one that will return Zebley to his element as a tireless investigator, pursuing the Russia investigation with all the patience and doggedness of his years-long hunt for al Qaeda suspects across the globe.

Journalist Garrett M. Graff (@vermontgmg) can be reached at garrett.graff@gmail.com. He is the author of The Threat Matrix: Inside Robert Mueller’s FBI.