Washington (CNN) The FBI asked last month to interview the intelligence community whistleblower who first raised concerns about President Donald Trump's interactions with Ukraine that ultimately sparked the House impeachment inquiry, a source familiar with the request confirmed to CNN.

In mid-October, the FBI's Washington Field Office reached out to lawyers for the whistleblower and asked to interview the anonymous individual regarding the complaint filed with the Intelligence Community Inspector General in August, the source said.

The whistleblower's legal team and FBI have been in contact regarding the request, which was made weeks after the Justice Department said it had decided not to pursue a campaign finance investigation based on the call, according to the source.

It is not clear why the FBI wants to interview the whistleblower, and the source did not elaborate on the communication between the two sides. Yahoo News first reported the interview request.

The Justice Department earlier this year reviewed the contents of the whistleblower complaint as a potential violation of campaign finance law by the President. Prosecutors from the Justice Department's criminal division who did that review, including a number of career attorneys, decided against moving forward with a full investigation into potential campaign finance violations, senior Justice Department officials said in September.

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