Former Trump campaign adviser Carter Page was the target of a secret surveillance warrant since at least 2014, much earlier than previously believed.

That revelation, reported by CNN on Thursday, raises the possibility that Page, a Manhattan-based energy consultant, was under surveillance while he served on the Trump campaign.

It was reported in April that the FBI obtained a warrant under the Foreign Intelligence Surveillance Act (FISA) against Page in September. The New York Times reported at the time that U.S. officials obtained the warrant after determining that Page was no longer part of the Trump campaign. Investigators did not want to cross the line of investigating someone involved in a political campaign, an official told The Times.

It is not clear whether Page was under surveillance continuously since 2014 or whether the FBI applied for a new warrant in September. Federal judges overseeing the court that approves FISA warrants typically place a time limit on how long surveillance can be conducted against a target. (RELATED: Carter Page Has Been Interviewed By The FBI Five Times, ‘Give Or Take’)

Page joined the Trump campaign in March as an unpaid foreign policy adviser. Though he has said that he never met with Trump and played a small part on the foreign policy team, Page’s contacts with Russian nationals — as well as a trip to Moscow in July — have made him the subject of intense speculation regarding potential collusion between the Trump campaign and Russian government.

Page, who has worked in the past as a banker for Merrill Lynch in Moscow, was also named in a dossier compiled by former British spy Christopher Steele that was published by BuzzFeed in January. The dossier, which was financed by an opposition research firm working for an ally of Hillary Clinton’s, alleged that Page negotiated in secret with a Russian oil executive and Kremlin insider during his Moscow trip.

Page has denied all of the allegations made in Steele’s document, which he refers to as the “dodgy dossier.”

The FBI reportedly relied on the dossier to open an investigation into potential collusion. The dossier was also reportedly cited in the FBI application for the FISA warrant on Page. The warrant application also reportedly cited a Russian spy’s attempts to recruit Page back in 2013.

Page has denied that he was recruited by the spy. He says he was interviewed by FBI agents investigating that case, which ended in charges against the Russian operative. Page has also been interviewed for 10 hours by FBI agents investigating potential Trump campaign collusion with Russia.

Reached for comment after CNN published its report, Page railed against what he says is illegal surveillance conducted by FBI Director James Comey and President Obama.

“As usual, today’s report covered many additional ‘alleged’ disclosures under the de facto FILTH Act (Freedom of Illegal Leakers to Terrorize Human),” Page told TheDC through text message.

He also criticized the “illegitimate FISA kangaroo court warrant,” which he asserts was obtained with “false evidence” provided by Comey.

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