James Comey. Zach Gibson/Getty Images A former FBI agent told Business Insider they were "surprised" at the timing of FBI Director James Comey's firing last week and that the ordeal would lead to increased camaraderie at the bureau.

The former agent, who spoke on background to provide their candid thoughts on the fallout from President Donald Trump's firing of Comey on Tuesday, said it "caught everybody off guard."

"There wasn't any real triggering event," said the former agent, who served in the bureau for more than two decades. "Whenever there is something like this, there is some kind of lead-up, and it's not totally caught by surprise. There's at least some rumors."

In his letter firing Comey, Trump cited a recommendation from Deputy Attorney General Rod Rosenstein that blasted Comey for his handling of the investigation into Hillary Clinton's use of a private email server while she was secretary of state. But Trump later told NBC News that he would have fired Comey "regardless" of the recommendation.

Comey also presided over a counterintelligence investigation, which he announced publicly during a March hearing, that included looking into whether the Trump campaign colluded with Russian officials. The same day Comey was fired, a grand jury issued the first subpoenas in that investigation, seeking business records of associates of ousted National Security Adviser Michael Flynn, CBS reported.

Trump said during that NBC interview that he received multiple personal assurances from Comey, whom he called a "showboat" and a "grandstander," that he was not personally under investigation. Trump later tweeted that Comey "better hope that there are no 'tapes' of our conversations before he starts leaking to the press!"

Meanwhile, the White House pushed a narrative that Comey had lost the faith of his rank-and-file agents. Deputy White House press secretary Sarah Huckabee Sanders said at a briefing last week that many FBI employees told her they were "very happy with the president's decision."

Donald Trump. AP Photo/Evan Vucci

The former agent left the FBI before Comey's confirmation as director in 2013 but maintains strong connections to the organization and has worked with Comey previously. They said he enjoyed a "broad" level of general support at the time of his firing.

But the former agent said Comey's handling of the Clinton email investigation created a "sharp division" in the FBI, and that with Trump looking to fill the vacancy in the coming days, Clinton was "not completely out of the woods" regarding the email controversy.

"Trump's unpredictable," the former agent said. "If he goes back to the [campaign], that's still on the table — in my opinion, legitimately on the table."

The former agent said had Comey been fired after his July press conference, in which he laid out the case against Clinton and said the FBI would not recommend charges, those within the organization would have been less surprised.

"But now that the dust has settled and he's moved on and done other things and seemed to be doing OK, then now you're going to be much more shocked," the former agent said.

Surprising as well was the tone of Rosenstein's letter, the former agent said, adding that there was "no way" that letter was put together within the deputy attorney general's first two weeks on the job. ABC News reported on Friday that Comey was "furious" with the lack of respect from the White House.

"So whoever was crafting that communication I think had been working on it for a while," the former agent said. "It is surprising to have that tone for a guy who's only a couple of weeks on the job. Somebody took the time to put this together. It is a little surprising that he would agree in this short period of time, unless he agreed with it all."

As for whether Comey's firing would calm the FBI's Russia investigation, the former agent said the opposite would happen. If Trump's goal was to quash the investigation, this move "backfired," they said.

"That sort of stuff fires them up more than it tones them down," the former agent said. "Nobody gets toned down."

The former agent, however, said Comey left without a major event to help pull the bureau together.

"He was still fairly new, and he didn't have an event like 9/11 like Mueller had to kind of pull everybody together," the former agent said, referring to former Director Robert Mueller. "And so I think the organization is a little more divided in that you don't have that rallying event."

The former agent paused for a second.

"This might rally them," they said.