The timeline of the Intelligence Community whistleblower complaint stemming from a discussion between President Trump and Ukrainian President Volodymyr Zelensky shows just how quickly a controversial phone call turned into the calls for impeachment that have gripped Washington, D.C.

July 25, 2019 — Trump and Zelensky spoke by phone for roughly half an hour, while top officials such as Secretary of State Mike Pompeo listened in. Trump asked for a "favor" from Ukraine in investigating a conspiracy theory related to the cybersecurity firm CrowdStrike, which determined the Russians hacked the Democratic National Committee’s email systems, an assessment special counsel Robert Mueller and the U.S. Intelligence Community agreed with. Trump also urged the Ukrainian leader to look into any Ukrainian involvement in the 2016 election. Trump brought up his request related to CrowdStrike immediately after Zelensky asked about purchasing anti-tank weaponry, known as Javelins, from the United States. Trump also talked about "the other thing," suggesting the Ukrainians investigate allegations of corruption related to 2020 Democrat Joe Biden and his son, Hunter. Trump urged Zelensky to speak with Rudy Giuliani, his personal attorney, and Attorney General William Barr. Giuliani had spent months publicly urging Ukraine to investigate the Bidens, but the Justice Department quickly made it clear that Barr wasn’t associated with the effort.

July 25, 2019 through Aug. 12, 2019 — The whistleblower said he spoke with numerous U.S. government officials with knowledge of the call and other activities within the White House, the State Department, and elsewhere connected to the Trump administration and its Ukraine policy. The New York Times reported that the whistleblower had a CIA colleague communicate some concerns to the CIA’s top lawyer, after which the whistleblower spoke with a staff member on the House Intelligence Committee days before the complaint was officially submitted.

July 26, 2019 — The whistleblower wrote that now-resigned U.S. Special Envoy to Ukraine Kurt Volker traveled to Kyiv to meet with Zelensky “and a variety of Ukrainian political figures” and gave “advice to the Ukrainian leadership about how to ‘navigate’ the demands that President [Trump] had made” to Zelensky. Text messages among Volker, U.S. Ambassador to the European Union Gordon Sondland, and U.S. Chargé d’Affaires to Ukraine William Taylor in the following weeks show them pushing Ukraine to declare its intent to investigate issues related to the 2016 election and Burisma.

Aug. 2, 2019 — The whistleblower said “multiple U.S. officials” told him about an Aug. 2 trip by Giuliani to Madrid to meet with Zelensky adviser Andriy Yermak in person, characterizing the meeting as a “direct follow-up” to the Trump-Zelensky call about the “cases” they’d discussed. Giuliani disputed this, saying the meeting was already in the works before that call. Giuliani spoke with Yermak prior to July 25, and that call is mentioned by Zelensky to Trump. Giuliani says Volker put him “in direct contact” with Yermak days before the Trump-Zelensky call and that Yermak indicated Ukraine was open to pursuing these investigations. The whistleblower also said Giuliani reached out to other Ukrainian officials, too.

Aug. 12, 2019 — The whistleblower complaint, addressed to Senate Intelligence Committee Chairman Richard Burr of North Carolina and House Intelligence Committee Chairman Adam Schiff of California, was submitted to and received by the office of the Intelligence Community inspector general, led by Michael Atkinson. The whistleblower complaint alleged, among many things, that U.S. officials believed that the Trump-Zelensky call transcript was “locked down” in a potentially “abusive” way and were “deeply concerned” by Giuliani’s “circumvention of national security decision-making.”

Aug. 26, 2019 — Atkinson sent a letter to acting Director of National Intelligence Joseph Maguire, letting him know about the existence of the complaint, summarizing its claims, informing Maguire that Atkinson determined that the whistleblower “appears credible” and that the complaint is of “urgent concern,” and recommending the information be provided to the appropriate congressional committees.

Sept. 2, 2019 — At an overseas press conference, Vice President Mike Pence was asked about the meeting he’d had with Zelensky the day before and, first, whether he’d discussed Joe Biden “at all” and, secondly, whether he could assure Ukraine that the hold-up of money has “absolutely nothing to do with efforts, including by Rudy Giuliani, to try to dig up dirt on the Biden family.” Pence replied that “on the first question, the answer is no.” But Pence then went on at length, adding, “but as President Trump had me make clear, we have great concerns about issues of corruption.”

Sept. 3, 2019 — A group of five bipartisan senators wrote to Office of Management and Budget Director Mick Mulvaney to “express our deep concerns” about nearly $400 million dollars in military aid for Ukraine being delayed.

Sept. 9, 2019 — Atkinson wrote a letter to Schiff and Rep. Devin Nunes of California informing the Intelligence Committee chairman and ranking member of the existence of the whistleblower complaint and that Maguire had informed him that the complaint was not required to be handed over to Congress. Atkinson disagreed, saying that while he believed Maguire was “acting in good faith," he didn’t think Maguire’s decision was “consistent with past practice.” That same day, three Democrat-led committees announced a “wide-ranging investigation” into reports that Trump and Giuliani had pressured Ukraine to help with Trump’s 2020 reelection bid.

Sept. 10, 2019 — Schiff wrote to Maguire that he had been made aware of the whistleblower complaint and claimed that Maguire was “required” to hand it over immediately.

Sept. 11, 2019 — Republican Sen. Rob Portman of Ohio said he spoke with Trump “to ask him to release the security funds for Ukraine” and Trump agreed to release the money that day.

Sept. 13, 2019 — Schiff made the existence of the whistleblower complaint public after Maguire informed him that day that he was declining to provide him with the complaint, with Schiff accusing Maguire of improperly withholding the information from Congress and issuing a subpoena to compel Maguire to hand the complaint over to Congress. That same day, Jason Klitenic, the general counsel for the Office of the Director of National Intelligence, wrote a letter to Atkinson informing him that, after consulting with the Justice Department, Maguire had determined “that no statute requires disclosure of the complaint” to Congress because the allegations in the complaint didn’t relate to the conduct of a member of the Intelligence Community or to anyone under Maguire’s supervision.

Sept. 17, 2019 — Atkinson wrote to Schiff and Nunes that himself and Maguire were “at an impasse” due to “unresolved differences" and informed the congressional leaders that he was bound by the determination made by Maguire not to hand the complaint over, although he “respectfully disagreed with it.” That same day, Schiff went on MSNBC where he was asked whether he had heard from the whistleblower and misleadingly stated that “we have not spoken directly with the whistleblower" even though an Intelligence Committee staff member had spoken with the whistleblower and had made Schiff aware of at least some details related to the whistleblower’s allegations.

Sept. 18, 2019 — Schiff informed Maguire that he was accepting his offer to testify on Sept. 26, 2019.

Sept. 19, 2019 — Schiff met with Atkinson behind closed doors. That same day, the Washington Post claimed that the whistleblower complaint “made by an intelligence official centers on Ukraine” and that it “involved communications with a foreign leader and a 'promise' that Trump made.”

Sept. 20, 2019 — The Wall Street Journal wrote that the whistleblower complaint alleged that Trump had “repeatedly pressured the president of Ukraine to investigate Joe Biden’s son.” Biden declared that “such clear-cut corruption damages and diminishes our institutions of government by making them tools of a personal political vendetta” and called for the Trump-Zelensky call transcript to be released. Trump defended the call as “totally appropriate.”

Sept. 24, 2019 — Democratic House Speaker Nancy Pelosi announced that “the House of Representatives is moving forward with an official impeachment inquiry.”

Sept. 25, 2019 — The Trump-Zelensky call transcript memo was released by the White House.

Sept. 26, 2019 — The whistleblower complaint was declassified and made public. Maguire also testified in front of the House Intelligence Committee, where he said he believed the whistleblower had “acted in good faith.”