A top FBI official who had a role in overseeing investigations into both Hillary Clinton Hillary Diane Rodham ClintonButtigieg stands in as Pence for Harris's debate practice Senate GOP sees early Supreme Court vote as political booster shot Poll: 51 percent of voters want to abolish the electoral college MORE and the Trump campaign will retire at the end of the year.

Bill Priestap, who currently serves as assistant director of the FBI's counterintelligence division, will leave the bureau after 20 years, The Wall Street Journal reported Tuesday.

His departure is unrelated to the 2016 investigations and the questions that have been raised about them, the Journal reported.

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The FBI said in a statement to the newspaper that Priestap “became eligible to retire and has chosen to do so after 20 years of service."

Priestap was involved in the FBI's investigation into Russian interference in the 2016 election and whether Russians colluded with the Trump campaign, and he was also part of the bureau's investigation into Clinton's use of a private email server while she was secretary of State.

When Priestap leaves the FBI, there will be no high-ranking officials who were involved in both investigations left at the bureau, according to the Journal.

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Counterintelligence agent Peter Strzok was fired in August after facing criticism for sending critical texts about Trump during the 2016 campaign. Priestap supervised Strzok before he was fired.

Trump has been highly critical of the FBI and the Department of Justice while he has served as president, frequently saying that there should be further investigations into Clinton and that the Russia probe should come to an end.