The Democratic operative arrested and charged with battery against the female campaign manager for Nevada gubernatorial nominee Adam Laxalt was employed at the George Soros-funded American Bridge for months, despite a reputation on Capitol Hill for what sources described as “hostile” tactics.

Wilfred M. Stark III, who goes by Mike, was arrested Tuesday evening in Las Vegas, after Laxalt campaign manager Kristin Davison accused him of grabbing and yanking her arm and refusing to let go. Las Vegas City Marshals arrested Stark, who was later released.

Stark, who was a reporter for American Bridge 21st Century, was fired Wednesday night in the wake of the incident. A statement from the David Brock-founded organization said that “an incident with a member of Adam Laxalt’s campaign” had taken place, and “one of our employees” had been relieved of his duties “effective immediately.” The statement did not identify Stark or Davison.

Fox News is told that during the arrest, Stark explained to police that this was “his job” and he “does this for a living.”

But the Las Vegas altercation is just the latest in a series of incidents involving Stark, before and during his time with American Bridge. The organization did not respond to repeated requests for information about what the group knew of Stark's history and conduct.

Several staffers for Republican lawmakers on Capitol Hill told Fox News that Stark is notorious for aggressive behavior when dealing with members and their aides.

“He is widely known among members and staffers as being a real problem on Capitol Hill—not for asking tough questions, but because he’s so openly hostile and combative,” a GOP aide told Fox News. “It’s become a real security concern.”

The aide added: “Aggressive, belligerent, inappropriate—no words do this guy justice.”

“We deal with trackers all the time, but he is far and above more hostile and unprofessional than any others,” the aide said.

Conn Carroll, communications director for Sen. Mike Lee, R-Utah, told Fox News that last month, Stark “followed, filmed and harassed” Lee in the basement of the Russell Senate building on the way to the hearing for now-Supreme Court Justice Brett Kavanaugh.

“I’ve known Mike Stark for literally over a decade. This is who he is. American Bridge knows who he is and what he does and they hired him accordingly,” Carroll tweeted Wednesday morning. “He was in Senate office buildings harassing me and my boss during the Kavanaugh hearings. Those are the facts. Open your eyes.”

He added minutes later: “This idea that American Bridge randomly ‘got stuck with’ Mike Stark is willfully and ignorant blindness. He has been doing this for years. American Bridge knew exactly who they were hiring and what he does.”

Sen. Rand Paul, R-Ky., tweeted on Thursday questioning whether the group was inciting violence towards Republicans.

"Soros paid protester arrested. Same group operates inside congressional office buildings. Are democrats paying to incite violence?" Paul tweeted.

GOP Virginia Rep. Barbara Comstock also tweeted that Stark “harassed our campaign on the 4th of July.”

And on June 25, House Intelligence Chairman Devin Nunes, R-Calif., posted a photo of Stark, tweeting: “Anyone know this dude? Kept chasing me around the Capitol with a camera phone today…please RT.”

More recently, Stark was a regular presence on Capitol Hill during the fight over now-Justice Brett Kavanaugh's Supreme Court confirmation and the sexual assault allegations against him. Capitol Police sometimes would escort lawmakers away from Stark as he fired off questions.

Stark was hired by American Bridge in January. The following month, he was found guilty of disorderly conduct and ordered to pay a $500 fine in connection with an October 2017 incident at a Virginia parade, where then-GOP gubernatorial candidate Ed Gillespie was campaigning. Stark, then an employee of ShareBlue Media, was arrested after he approached a vehicle carrying Gillespie.

Fairfax County Police Lt. Peter Massoro testified that the Gillespie campaign expressed concern about Stark lurking around the vehicle and feared he might be violent, WRC-TV reported. Massoro testified that when he ordered Stark to move out of the street as the vehicle prepared to join the parade, he snapped at the officer: "[Expletive] this. I'm a [expletive] reporter. You can't tell me what to do." Stark reportedly was arrested after he responded to further orders to move onto the sidewalk with more profanity.

A month after his disorderly conduct conviction, Stark faced more allegations after he confronted Heather Swift, a female staffer for Interior Secretary Ryan Zinke, following a March 15 congressional hearing. According to a Capitol Police report, Stark approached Zinke after a House hearing and started yelling at him. As Zinke continued walking out of the hearing room, the report said Stark “used his full body to push” Swift as she tried to follow her boss.

Stark was arrested and charged with simple assault. Swift told the Associated Press at the time that she had pressed charges to obtain a "stay-away order" against Stark, whom she said had been removed from an elevator two days earlier on March 13 after he tried to force his way on to confront Zinke and his staff.

"[Stark] is a big guy. He came up behind me fast, aggressive and very physical,” Swift said. “Who knows what this lunatic was thinking?”

American Bridge said in response that Stark denied the allegations and added, "We are gathering all the facts and information surrounding this event."

The organization did not respond to requests Wednesday for information about whether it knew of Stark's October 2017 disorderly conduct arrest when it hired him earlier this year. It also did not respond to inquiries about whether anyone at the organization had reservations about Stark's hiring or keeping him employed after his February conviction or his March assault charge.

American Bridge was founded in 2010 by Brock, who also founded liberal watchdog group Media Matters.

Fox News' Peter Doocy contributed to this report.