Paul Sperry from RealClearInvestigations has outlined the CIA “whistle-blower” who originated the hearsay complaint against President Trump as Eric Ciaramella.
According to the researched outline, Ciaramella worked closely with Democrat operative, Alexandra Chalupa in 2016 to advance the anti-Trump effort; and this year Ciaramella worked closely with HPSCI Chairman Adam Schiff’s staff to continue his efforts.

(RCPI) […] Federal documents reveal that the 33-year-old Ciaramella, a registered Democrat held over from the Obama White House, previously worked with former Vice President Joe Biden and former CIA Director John Brennan, a vocal critic of Trump who helped initiate the Russia “collusion” investigation of the Trump campaign during the 2016 election.
Further, Ciaramella (pronounced char-a-MEL-ah) left his National Security Council posting in the White House’s West Wing in mid-2017 amid concerns about negative leaks to the media. He has since returned to CIA headquarters in Langley, Virginia.

“He was accused of working against Trump and leaking against Trump,” said a former NSC official, speaking on condition of anonymity to discuss intelligence matters.
Also, Ciaramella huddled for “guidance” with the staff of House Intelligence Committee Chairman Adam Schiff, including former colleagues also held over from the Obama era whom Schiff’s office had recently recruited from the NSC. (Schiff is the lead prosecutor in the impeachment inquiry.)
And Ciaramella worked with a Democratic National Committee operative who dug up dirt on the Trump campaign during the 2016 election, inviting her into the White House for meetings, former White House colleagues said. The operative, Alexandra Chalupa, a Ukrainian-American who supported Hillary Clinton, led an effort to link the Republican campaign to the Russian government. “He knows her. He had her in the White House,” said one former co-worker, who requested anonymity to discuss the sensitive matter.  (read more)