John Brown, a special agent in charge of the FBI’s San Diego Field Office, has been tapped for the organization’s top counterintelligence position.

Brown will replace Bill Priestap, who served as assistant director of the FBI’s counterintelligence division, sources familiar with the matter told The Hill.

An FBI official confirmed to The Hill that Brown has been appointed to serve as the assistant director, noting that the bureau has not publicly announced it.

ADVERTISEMENT

Priestap, who has 20 years of service to the FBI, was the last top official to have a role overseeing investigations into both Hillary Clinton Hillary Diane Rodham ClintonJoe Biden looks to expand election battleground into Trump country Biden leads Trump by 12 points among Catholic voters: poll The Hill's Campaign Report: Biden goes on offense MORE and the Trump campaign.

Brown, an army veteran who joined the FBI as a special agent in 1999, has focused on counterintelligence, counterterrorism and cyber crime cases throughout his career, according to his FBI biography page.

His first assignment was in the Chicago Field Office, where he focused largely on counterintelligence cases and deployed to Iraq in 2004.

Most recently, starting in February 2018, Brown began to serve as the FBI special agent in charge of the San Diego Field Office.

Brown also reportedly worked a short time with special counsel Robert Mueller Robert (Bob) MuellerCNN's Toobin warns McCabe is in 'perilous condition' with emboldened Trump CNN anchor rips Trump over Stone while evoking Clinton-Lynch tarmac meeting The Hill's 12:30 Report: New Hampshire fallout MORE on the Russia probe.

Former FBI lawyer Lisa Page testified before House investigators last year that Brown and Mueller were “not a good match,” according to an Epoch Times report, which cited obtained copies of her closed-door transcript.

Then-counterintelligence agent Peter Strzok, who had an extramarital affair with Page during the 2016 election, was then brought over to work on the Russia investigation. Strzok came under fire last year after his text messages to Page surfaced, which showed him making disparaging remarks about President Trump Donald John TrumpBubba Wallace to be driver of Michael Jordan, Denny Hamlin NASCAR team Graham: GOP will confirm Trump's Supreme Court nominee before the election Southwest Airlines, unions call for six-month extension of government aid MORE and other political figures during the 2016 election.

A spokesperson for Mueller’s team declined to comment on whether Brown has previously served on the team.

In a May interview with the San Diego Tribune, Brown defended bureau employees in response to question about Trump’s attacks on the FBI and the president’s decision to fire former FBI Director James Comey James Brien ComeyDemocrats fear Russia interference could spoil bid to retake Senate Book: FBI sex crimes investigator helped trigger October 2016 public probe of Clinton emails Trump jabs at FBI director over testimony on Russia, antifa MORE.

“I’m not motivated or demotivated by the news. I’m committed to our craft, and that is protecting the American people and upholding the Constitution — that is our mission,” he told the California paper.

“So we have to keep our heads down and continue to do what we do because that’s what’s expected, and we can’t have any gaps or seams in that. I think most FBI employees see it that way. I think in the end it’s noise what’s happening, and it is sad. I think this will pass,” he continued.

When asked about Trump’s decision to fire Comey, Brown said the show must go on.

“When [former FBI Director J. Edgar] Hoover died, we opened up the next day. You recognize [Comey] was an important member of this organization, but at the same time the organization is bigger than him and the mission is bigger than all of us. That’s what we have to keep our focus on,” he told the San Diego Tribune.

Brown, who described himself as aggressive due to his counterterrorism background, said he applied a similar approach when he got moved to deal with cyber threats in the bureau.

“ [They said], ‘we need some aggressiveness,’ so I was brought up [to the FBI Headquarters] for that mindset,” he told the Tribune.

“It was eye-opening. I think I played a small part of building some of the edifices that still stand today, from Cyber Watch, to in terms of how we look at cases — not looking at the IP addresses and data, but in terms of there are people behind the keyboard,” he added.