On Monday evening, The Washington Post revealed the identity of the FBI informant at the center of President Trump’s recent frustrations. Over the course of 2016, emeritus professor at the University of Cambridge Stefan A. Halper contacted three people affiliated with Trump’s foreign-policy advisory team, two of whom were subjects of known FBI investigations beginning that summer.

Trump and his allies have criticized Halper’s contribution to the FBI’s investigation as an unwarranted intrusion into Trump’s campaign itself. Trump has repeatedly insisted that reports about Halper’s work showed bias on the part of the FBI that was a scandal “bigger than Watergate.”

What’s known about Halper’s outreach, though, suggests a modest effort to get information from particular people who were already the subject of FBI scrutiny. Two people he contacted, foreign policy advisers George Papadopoulos and Carter Page, initially met Halper in London — not, as some have implied, after Halper took some sort of position with the Trump campaign. (He did not do so.)

In light of the attention drawn to Halper by the president’s criticisms, we’ve put together a timeline showing how his known outreach overlapped with other investigatory efforts on the part of the FBI. Both Papadopoulos and Page were already being investigated by the FBI or had already been interviewed by the agency before Halper contacted them.

Items in bold involve Halper directly.

Pre-campaign

2012. Halper begins a relationship with the Defense Department, working with a Pentagon group called the Office of Net Assessment.

January 2013. Page meets a Russian foreign intelligence officer named Victor Podobnyy at a conference in New York.

March 2013. The FBI interviews Page after surveillance picks up Podobnyy mentioning Page as a potential target for recruitment.

Aug. 25, 2013. In a letter to a publisher, Page claims that for six months he has “had the privilege to serve as an informal advisor to the staff of the Kremlin in preparation for their Presidency of the G-20 Summit next month.”

Feb. 28, 2014. Michael Flynn participates in a national security seminar at Cambridge University organized by Halper and Richard Dearlove, the former head of Britain’s intelligence service.

The Trump campaign begins

June 16, 2015. Trump announces his candidacy.

Summer 2015. Hackers believed to be linked to the Russian Federal Security Service (FSB) gain access to the network of the Democratic National Committee, according to U.S. intelligence agencies.

Aug. 25, 2015. Sam Clovis joins Trump’s campaign after working with the failed presidential bid of Rick Perry. He serves as a policy adviser and works with Trump’s foreign policy team.

Dec. 10, 2015. Flynn travels to Moscow to participate in an event celebrating the 10th anniversary of the Kremlin-funded news network Russia Today (now RT).

March 2016. The FBI again interviews Page.

March 6, 2016. Papadopoulos is asked to join the Trump campaign as an adviser on foreign policy issues. He had previously been advising Ben Carson’s unsuccessful presidential campaign. His initial conversation about joining the campaign was with Clovis, who, Papadopoulos told prosecutors, suggested that improving relations with Russia was a key campaign goal. (Clovis has denied that.)

March 14, 2016. Papadopoulos meets in Italy with a London-based professor named Joseph Mifsud, director of the London Academy of Diplomacy. Until he learns that Papadopoulos is tied to the Trump campaign, Mifsud is uninterested in talking.

March 21, 2016. Trump publicly identifies Papadopoulos and Page as part of his foreign policy advisory team.

March 31, 2016. The foreign policy advisory team meets. Trump tweets about it.

April 18, 2016. Papadopoulos is introduced via email to someone who has contacts at Russia’s Ministry of Foreign Affairs. Papadopoulos and the contact begin communicating regularly to try to set up a meeting between Trump and Putin.

April 26, 2016. Papadopoulos is told by Mifsud that the Russians have “dirt” on Democratic presidential candidate Hillary Clinton. “They have thousands of emails,” he is told. The next day, he emails senior campaign adviser Stephen Miller to say he had “some interesting messages coming in from Moscow about a trip when the time is right.”

May 2016. During a night of drinking in London, Papadopoulos tells Australian High Commissioner to Great Britain Alexander Downer that he is aware that Russia has dirt on Clinton.

July 7, 2016. Page travels to Moscow to give a speech. The next day, he sends a memo to campaign staff with an overview of his travel. It reads, in part, “Russian Deputy Prime Minister and [New Economic School] Board Member Arkadiy Dvorkovich also spoke before the event. In a private conversation, Dvorkovich expressed strong support for Mr. Trump and a desire to work together toward devising better solutions in response to the vast range of current international problems.”

July 11 and 12, 2016. Page meets Halper at a Cambridge conference called Race to Change the World. It is focused on “the 2016 U.S. presidential election and the implications that this will have for future U.S. foreign policy.” The two continue to communicate over email.

July 11 or 12, 2016. Trump campaign staffers apparently intervene with the committee developing the Republican Party’s national security platform to remove language calling for arming Ukraine against Russian aggression.

July 22, 2016. WikiLeaks begins releasing emails stolen from the Democratic National Committee.

The investigation begins

July 31, 2016. The FBI opens its counterintelligence investigation into Russia’s efforts to interfere in the 2016 election. The investigation is triggered when Australian authorities contact the agency — realizing that Papadopoulos’s May mention of Russian dirt to Downer, the diplomat, was validated by the release of stolen data.

August 2016. Papadopoulos seeks permission to travel to Russia to facilitate a meeting between Trump and Putin. After being discouraged from doing so earlier in the year, Clovis tells Papadopoulos to do so “if feasible” — but not as a representative of the campaign.

Aug. 31 or Sept. 1, 2016. Halper has coffee with Clovis. Clovis says that the subject of conversation was China, not Russia. Halper requests a second meeting, but it doesn’t happen.

Sept. 2, 2016. Halper contacts Papadopoulos offering to pay him to write a paper about oil fields in the Mediterranean and inviting him to London. Papadopoulos does so later that month, receiving $3,000 in payment.

Sept. 15, 2016. While in London, Papadopoulos has drinks with a woman who identifies herself as Halper’s assistant. He meets Halper at the Traveler’s Club. According to the New York Times, Halper asked if Papadopoulos knew about any interference efforts, which Papadopoulos denied — to Halper’s annoyance.

Sept. 23, 2016. Yahoo News reports on possible contacts between Page and Russian authorities, based on information collected by former British intelligence officer Christopher Steele as part of his work for the firm Fusion GPS.

Sept. 26, 2016. Page announces his departure from the Trump campaign.

Oct. 21, 2016. The FBI is granted a warrant to surveil Page.

Nov. 8, 2016. Trump is elected president.

Sept. 2017. Page and Halper are in contact for the last time, according to an interview Page gave the Daily Caller.

Late September 2017. The warrant to surveil Page, extended three times, expires.