WASHINGTON — Peter Strzok, the F.B.I. senior counterintelligence agent who disparaged President Trump in inflammatory text messages and helped oversee the Hillary Clinton email and Russia investigations, has been fired for violating bureau policies, Mr. Strzok’s lawyer said Monday.
Mr. Trump and his allies seized on the text messages — exchanged during the 2016 campaign with a former F.B.I. lawyer, Lisa Page — in assailing the Russia investigation as an illegitimate “witch hunt.” Mr. Strzok, who rose over 20 years at the F.B.I. to become one of its most experienced counterintelligence agents, was a key figure in the early months of the inquiry.
Along with writing the text messages, Mr. Strzok was accused of sending a highly sensitive search warrant to his personal email account.
The F.B.I. had been under immense political pressure by Mr. Trump to dismiss Mr. Strzok. The president again tweeted about Mr. Strzok on Monday.
Mr. Strzok’s lawyer said the deputy director of the F.B.I., David Bowdich, had overruled the bureau’s Office of Professional Responsibility, which said Mr. Strzok should be suspended for 60 days and demoted.
“The decision to fire Special Agent Strzok is not only a departure from typical bureau practice, but also contradicts Director Wray’s testimony to Congress and his assurances that the F.B.I. intended to follow its regular process in this and all personnel matters,” said the lawyer, Aitan Goelman, referring to the F.B.I. director, Christopher Wray.
“This decision should be deeply troubling to all Americans,” Mr. Goelman said. “A lengthy investigation and multiple rounds of congressional testimony failed to produce a shred of evidence that Special Agent Strzok’s personal views ever affected his work.”
It is not clear why Mr. Bowdich overruled the Office of Professional Responsibility. A spokeswoman for the F.B.I. did not respond to a message seeking comment.
The Office of Professional Responsibility had made its recommendation about Mr. Strzok after his conduct was laid out in a wide-ranging inspector general’s report in June. Mr. Strzok had testified before the House in July about how he had not allowed his political views to interfere with the investigations he was overseeing.
Mr. Strzok’s text message exchanges with Ms. Page demonstrated animosity toward Mr. Trump. In one, Ms. Page asks: Trump is “not ever going to become president, right? Right?!” Mr. Strzok responds: “No. No he won’t. We’ll stop it.” The inspector general, who uncovered the messages, found no evidence that the pair imposed their political views on their investigative decisions but cited that exchange as “not only indicative of a biased state of mind but, even more seriously, implies a willingness to take official action to impact the presidential candidate’s electoral prospects.”
The report by the inspector general, Michael E. Horowitz, that preceded Mr. Strzok’s firing criticized his conduct in sending the texts; his use of personal email accounts to handle sensitive information; and a decision not to move swiftly enough to examine new emails related to the Clinton investigation just weeks before the 2016 election.
Mr. Horowitz said in his report that he was “deeply troubled” by the text messages. Hundreds exchanged over months were found in which the pair disparaged Mr. Trump and, to a lesser extent, Mrs. Clinton, exchanged work gossip and bantered.
Mr. Strzok became emblematic of Mr. Trump’s unfounded assertions that a so-called deep state of bureaucrats opposed to him was undermining his presidency. Mr. Trump contended that Mr. Strzok targeted the president and accused Mr. Strzok of being “treasonous” and a “disgrace.” Mr. Strzok told lawmakers that he never leaked information about the Russia inquiry, which could have upended the election and hurt Mr. Trump’s chances of becoming president.
After Mr. Horowitz uncovered the text messages, the special counsel, Robert S. Mueller III, who had by then taken over the investigation, removed Mr. Strzok from his team last summer. He was reassigned to the F.B.I.’s human resources division. Ms. Page, who had left Mr. Mueller’s team before the discovery of the text messages, quit the F.B.I. in May.
The inspector general’s report also took issue with the reaction by Mr. Strzok and other F.B.I. officials to the discovery of possible new evidence in the Clinton investigation, known internally as Midyear Exam, in late September 2016 on a laptop that belonged to the disgraced politician Anthony Weiner, the husband of a top Clinton aide.
At the time, Mr. Strzok was in the early stages of investigating whether any Trump associates had conspired with Russia’s interference in the presidential election, and nearly a month passed before agents and analysts began to act on the emails found on Mr. Weiner’s laptop. Mr. Horowitz could not rule out that Mr. Strzok had slow-walked the examination of the new emails to help Mrs. Clinton’s presidential bid.
“Under these circumstances, we did not have confidence that Strzok’s decision to prioritize the Russia investigation over following up on the Midyear-related investigative lead discovered on the Weiner laptop was free from bias,” he wrote.
The delays were merely the “result of bureaucratic snafus,” Mr. Strzok’s lawyer wrote last month in USA Today.
But the justifications for the delay were “unpersuasive” and had “far-reaching consequences,” the inspector general said. James B. Comey, the former F.B.I. director, has told investigators that if he had known about the emails earlier, it might have influenced his decision to alert Congress to their existence days before the election.
In addition, the inspector general said that Mr. Strzok had forwarded a proposed search warrant to his personal email account. The inspector general said the email, which included a draft of the search warrant affidavit, contained information that appeared to be under seal.
In a heated congressional hearing last month, Mr. Strzok expressed “significant regret” for the texts and rebutted the president’s attacks on the Russia inquiry. “This investigation is not politically motivated; it is not a witch hunt; it is not a hoax,” he said.
Mr. Strzok’s dismissal was not unexpected. He is the second senior F.B.I. agent to be fired as a result of the inspector general’s investigation. In March, Andrew G. McCabe, the former deputy director, was fired after the inspector general repeatedly faulted him for misleading investigators.
The firing was politically motivated, Mr. McCabe has said, as an effort to discredit him as a witness in the special counsel investigation.
Both men were fired before they were eligible for their pension and health benefits.
Mr. Strzok, 48, a graduate of Georgetown University, served as an officer in the United States Army before he joined the F.B.I. He held several key positions in the F.B.I., eventually becoming a top deputy in the counterintelligence division.
He handled many important espionage cases including one involving a former C.I.A. officer suspected of working for China and a group of Russian spies who had been working undercover in the United States.