So, I am puzzled. First, when did the Trump investigation begin?
In mid-March 2016, George Papadopoulos visited Rome, where he met Joseph Mifsud.
On 21 March 2016, the Trump Campaign announced that Georges Papadopoulos and Carter Page had joined the campaign as foreign policy advisers. Richard Haas not having joined.
On 24 March 2016, Papadopoulos met Joseph Mifsud and a woman Mifsud introduced as “Putin’s niece” in London. She was, in fact, Olga Polonskaya.
On 12 April 2016, Papadopoulos again met Mifsud in London.
On 25 or 26 April 2016, Mifsud again met Papadopoulos in London. Mifsud told Papadopoulos that the Russians had thousands of e-mails relating to Hillary Clinton. “This occurred after public knowledge that Clinton had deleted thousands of her emails, but before there was public knowledge of the hack of Democratic National Committee and of John Podesta‘s emails.” NB: So, the most reasonable thing to conclude would have been that the Russians had hacked into Clinton’s private server while she was Secretary of State.
In late April 2016, the DNC began to suspect that its computers had been hacked. The DNC informed the FBI and hired a private firm to investigate.
Papadopoulos knew an Israeli diplomat in London named Christian Cantor. Cantor’s girl-friend (now fiancé) is Erika Thompson, then a political counselor at the Australian High Commission. Thompson told High Commissioner (ambassador) Alexander Downer that he should meet Papadopoulos.
On 10 May 2016, over one or two gin-and-tonics, Papadopoulos told Downer that the Russians had damaging information about Hillary Clinton and might release it to harm her chances in the election.
[What Papadopoulos told Downer and Thompson] “was all good intel, relayed back to Australia in a cable written by Thompson. But it was what Papadopoulos had said about Russia, also detailed in the cable, that proved critical. He said the Russians might use some damaging material they had on Hillary Clinton, who was still some weeks from becoming the presumptive Democrat presidential nominee.” “But the cable came back to Canberra about an aide to Trump saying the Russians had some dirt on Hillary Clinton and were prepared to use it.”
According to Downer, “There was no suggestion — [neither] from Papadopoulos nor in the record of the meeting that we sent back to Canberra — there was no suggestion that there was collusion between Donald Trump or Donald Trump’s campaign and the Russians.” Moreover, neither Papadopoulos nor Downer remember any mention of e-mails in the discussion. Just “damaging information.” That could be many things.
“The Americans weren’t informed immediately about what Papadopoulos had said to Downer, but when it became known that the FBI suspected a Russian hack of Clinton emails, the information was shared with the Five Eyes intelligence partner.”
This is ambiguous. Is there a way to nail down the approximate/exact date when the Australians did share the information? The Russian hack of the DNC was known by 14 June 2016—not in late July 2016, when the FBI formally opened an investigation.
Also, is there a difference between formally and informally sharing? Did Downer share the information with the Ministry of Foreign Affairs in Australia, but withhold the information from his own Senior Advisor—Intelligence in the High Commission? If so, on what basis?
If Downer did share with the Senior Advisor, then did the Senior Advisor pass the information along to the CIA station-chief in London? If not, why not? This was a significant Russian attack on American democracy.
Did Erika Thompson share what she had heard with Christian Cantor? If she did, then did Cantor share this with his own ambassador and his ambassador with his government?
If either the CIA or Israel did learn of what Papadopoulos had said in early May 2016, would they have acted on that knowledge once the Russian hack became public in mid-June 2016? Would they have acted on it as soon as they discovered it?
Then, when Downer reported to Canberra, the DNC hack was not yet known. Yet in his subsequent interview Downer refers to e-mails.
On 14 June 2016, the DNC announced that its computers had been hacked by the Russians. And, what, the CIA and the NSA stood around with their hands in their pockets for the next six weeks?
Still, a pause ensued from mid-June to late July 2016. What was happening during this period?
On 22 July 2016, Wikileaks began publishing many of the stolen documents.
On 26 July 2016, the Australian government formally notified the United States of the report by Downer about Papadopoulos.
On 27 July 2016, Trump publically called for the Russians to release the 30,000 deleted e-mails from the Clinton computer. So, he’d heard something about Papadopoulos’s claims?
On 31 July 2016, the FBI formally opened “Operation Crossfire Hurricane.” FBI counter-intelligence officer Peter Strzok led the investigation and later served for a time on the staff of Special Counsel Robert Mueller.
In either late July or mid-August 2016, CIA Director John Brennan provided the FBI with “contacts and interactions between Russian officials and U.S. persons involved in the Trump campaign.” According to Brennan, these leads “served as the basis for the FBI investigation to determine whether such collusion [or] cooperation occurred.” NB: So the CIA had been investigating since when? In what ways? It was me, I’d spike Mifsud’s internet. Come to that, I’d spike the on-line stuff of Thompson and Cantor. Wouldn’t need a warrant for that. They’re all foreign, same as that Radical-Lutheran Merkel.
From 31 July to 2 August 2016, FBI agents interviewed both Downer and Thompson in London. From this point on, the Christian Cantor connection probably would have been known. “Burned,” as John Le Carre says.
 See: https://en.wikipedia.org/wiki/George_Papadopoulos#Involvement_in_Donald_Trump’s_presidential_campaign
 Since this was before the convention that nominated Secretary Clinton, it is fair to ask if they were trying to help Trump or help Senator Bernie Sanders.
 See: https://www.abc.net.au/news/2018-09-22/george-papadopoulos-alexander-downer-meeting-what-happened/10286868 ABC = Australian Broadcasting Corporation.
 See: https://www.nationalreview.com/news/ex-australian-diplomat-explains-why-he-turned-papadapoulos-info-over-to-fbi/ For the somewhat different account of the NYT, see: https://www.nytimes.com/2017/12/30/us/politics/how-fbi-russia-investigation-began-george-papadopoulos.html
 See: https://www.abc.net.au/news/2018-09-22/george-papadopoulos-alexander-downer-meeting-what-happened/10286868
 See: https://en.wikipedia.org/wiki/Crossfire_Hurricane_(FBI_investigation) Was the August instance additional information or is it a simple error in the article?