(President Donald Trump.Chris Kleponis/Pool - Getty Images)

This month's revelations about the investigation into Russia's election interference and President Donald Trump's campaign's ties to Moscow have come at a dizzying pace.

We learned that Robert Mueller, the special counsel leading the FBI's investigation, obtained a search warrant to examine Facebook accounts linked to Russia after the company announced that the "inauthentic" users had purchased more than $100,000 in ads during the election.

We also learned more details about the FBI's longtime interest in Trump's campaign chairman, Paul Manafort — and his overtures to a Russian oligarch last July.

The president's legal team, meanwhile, is clashing over how cooperative to be with Mueller, who is homing in on key White House players as he examines whether Trump sought to obstruct justice when he fired James Comey as FBI director.

Here is a look back at some of the month's most important developments:

• Facebook's Russia bombshell: Facebook announced on September 6 that it had shut down roughly 470 "inauthentic" accounts and pages that "were affiliated with one another and likely operated out of Russia." The accounts were connected to roughly $100,000 in ad purchases between June 2015 and May 2017, the company said in a statement.

• Mueller's Facebook search warrant: Mueller obtained a search warrant for records of the inauthentic Facebook accounts and the targeted ads they purchased during the election, according to The Wall Street Journal and CNN. The warrant indicates Mueller thinks he could obtain enough evidence to charge specific foreign entities with a crime.

• Manafort's wiretapping woes: US investigators reportedly obtained a so-called FISA warrant to wiretap Manafort before and after the election, CNN reported. The Journal reported later that the warrant covered only stored communications, not real-time conversations.

• 'Private briefings' and getting 'whole': Manafort offered "private briefings" about the campaign to a Russian oligarch and ally of Russian President Vladimir Putin just before the Republican National Convention, The Washington Post reported, adding that he asked his Russian-Ukrainian employee months earlier how he could use his new campaign role to "get whole."

• Mueller's obstruction net ensnares the White House: Mueller asked the White House for documents related to 13 categories deemed crucial to his investigation, including the FBI's interview in January with Michael Flynn, then the national security adviser, as well as a meeting Trump had in May with Russian diplomats in the Oval Office.

• Mueller zeroes in on a circle of Trump's closest aides: According to The Post, the special counsel wants to interview Sean Spicer, the former press secretary; Reince Priebus, the former chief of staff; Hope Hicks, the communications director; and Don McGahn, the White House counsel. Mueller also wants to talk to James Burnham, McGahn's deputy, and Josh Raffel, an aide to senior adviser Jared Kushner. All the aides were witness to critical events Mueller is looking into, The Post reported.

• A letter of intent for a Trump Tower Moscow: A few months after kicking off his presidential campaign, Trump signed a letter of intent to build a "Trump World Tower Moscow." His lawyer at the time, Michael Cohen, sent a letter to Putin's spokesman asking for his help with the project.

• Cohen defends himself amid a firestorm: Trump's personal lawyer told Vanity Fair that neither he nor the president was ever involved "with this Russian conspiracy." He also downplayed the Trump Tower Moscow controversy, calling it "business as usual and nothing more."

• The Russia probe encompasses Flynn's son: Mueller is scrutinizing Michael Flynn Jr. over work he did for Flynn Intel Group, the lobbying firm he and his father founded after the elder Flynn retired from the military, according to NBC News. Legal experts say Mueller's focus indicates Flynn Jr. could have some criminal liability, but that it could also be part of an effort to coerce his father into cooperating with the investigation.

• Trump's lawyers face off over the investigation: The defense attorney leading Trump's legal team is butting heads with the White House counsel over how much to cooperate with Mueller's investigation. Ty Cobb wants to hand over as much as possible to Mueller, while McGahn has resisted being too forthcoming in case Trump asserts executive privilege over their interactions, according to The New York Times.

• Susan Rice reveals why she requested to "unmask" the names of Trump associates: Rice told the House Intelligence Committee that she wanted to know why the crown prince of the United Arab Emirates traveled to New York in December without notifying the US government, CNN reported. As it turns out, the prince met with Flynn, Kushner, and Steve Bannon, the former White House chief strategist, at Trump Tower.

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