Carter Page, pictured above, was working for the FBI as a secret informant, posing as a Russian spy, when he was planted by the FBI into the Trump Presidential Campaign as an unpaid "volunteer".

The primary source is a one-page letter dated Sept. 25, 2016 from Page to then FBI Director James Comey. In it, Page admits "(interacting) with members of the U.S. intelligence community including the CIA and FBI for decades".

The letter, which Page released to the Washington Post, is linked here:

https://www.washingtonpost.com/r/2010-2019/WashingtonPost/2016/09/26/Editorial-Opinion/Graphics/2016.09.25_FBI_letter.pdf

A secondary source is:

https://theconservativetreehouse.com/2018/02/05/in-march-2016-carter-page-was-an-fbi-employee-in-october-2016-fbi-told-fisa-court-hes-a-spy/

Forget the Russian dossiers, all concocted by Hillary Clinton.

Page was the epicenter and catalyst of four warrants used to spy on Trump. He became a walking wire tap. Page has never been charged with a crime.

According to FISA, only foreign citizens, can be spied upon. FISA stands for Foreign Intelligence Surveillance Act. The FBI used Page as that hostile "foreigner".

The FBI transformed Page into a walking wire tap, acting as a dragnet with Trump as the target from May, 2016 through June, 2017.

Page quit the Trump Campaign on Sept. 25, 2016. A month later, the first of four FISA warrants were approved to snoop on Trump.

In November, 2016, Trump was elected President. He was inaugurated Jan. 20, 2017. In other words, Trump was being spied upon for the first six months of his Presidency by his own Justice Department and FBI.

Under FISA warrants, communications of targets like Page can be retroactively applied.

The FBI admits using Page as a Russian spy in at least one successful prosecution. It was in 2013. His sworn testimony was used to convict Evgeny Buryakov, a real Russian spy, in Manhattan Federal Court on March 11, 2016. Here is the Justice Department's press release of this case:

https://www.justice.gov/usao-sdny/pr/evgeny-buryakov-pleads-guilty-manhattan-federal-court-connection-conspiracy-work

The Washington Post also quoted Carter Page in court testimony that he "assisted the FBI with its investigation into the spy ring" of Buryakov. It is in paragraph 34 in the link below:

https://www.washingtonpost.com/politics/explanations-for-kushners-meeting-with-head-of-kremlin-linked-bank-dont-match-up/2017/06/01/dd1bdbb0-460a-11e7-bcde-624ad94170ab_story.html?utm_term=.da3f5a77b970

Before the trial began, the FBI vouched for the credibility of Carter Page. They told the jury that Page is a true American, someone they should trust because the FBI did.

https://www.reuters.com/article/us-russia-usa-espionage/fbi-penetrated-new-york-based-russian-spy-ring-using-hidden-recorders-idUSKCN0WB2NM

Page was the only American to have had his communications directly targeted with a FISA warrant in 2016 as part of the Russia probe, according to the Washington Post:

https://www.washingtonpost.com/world/national-security/fbi-obtained-fisa-warrant-to-monitor-former-trump-adviser-carter-page/2017/04/11/620192ea-1e0e-11e7-ad74-3a742a6e93a7_story.html?utm_term=.5a40d2739119

Page admitted to ABC News that he has "never spoken to Donald Trump in my life".

https://www.washingtontimes.com/news/2018/feb/6/carter-page-ive-never-spoken-donald-trump-my-life/

Page has never been charged with a crime. He was graduated from the U.S. Navy Academy in Annapolis. He served five years active duty.

https://intelligence.house.gov/uploadedfiles/carter_page_hpsci_hearing_transcript_nov_2_2017.pdf