A declassified House Intelligence Committee memo published on Feb. 2 showed that the FBI and Department of Justice (DOJ) had obtained a Foreign Intelligence Surveillance Act (FISA) warrant to spy on Carter Page, who was a volunteer for Donald Trump’s presidential campaign.

In obtaining the warrant, the memo states that the FBI and DOJ provided the Foreign Intelligence Surveillance Court—a federal court tasked with approving FISA warrants—knowingly unverified information provided by former British spy Christopher Steele.

The FBI and DOJ also didn’t disclose to the FISA court that Steele had been paid by Hillary Clinton’s presidential campaign and the Democratic National Committee, and that he was fiercely opposed to Trump, making the information provided highly questionable.

The memo also cites then-Deputy FBI Director Andrew McCabe as saying that the FBI could not have obtained the FISA warrant without the unverified Trump dossier produced by Steele.

So who is Carter Page, the man who was spied on for almost a year by the FBI?

Here are 4 things to know about him:

1. Carter Page has never spoken to Donald Trump in his life, nor communicated by email, text, or any other means, he told ABC News on Feb. 6.

2. Before being spied on by the FBI, Page had supported the agency as a witness in a case they were conducting against a Russian national accused of acting as an unregistered Russian agent in the United States. “I was a witness to a case they were doing. So I was supporting the FBI, ” Page told ABC News.

3. Page had not been present during the only time a group of foreign policy advisers for Trump met in March 2016. He told Fox News he was in Hawaii at the time.

4. Page filed a defamation lawsuit against Yahoo News and the Huffington Post over stories they published in 2016. Court documents show Page describing the Yahoo News article as “a highly misleading article filled with false allegations.”

Steele, who had been hired by Fusion GPS to produce the Trump dossier, said in a separate legal case in the UK, that he had briefed Yahoo News, alongside The New York Times, The Washington Post, CNN, and The New Yorker, about the contents of the unverified dossier.