The project in question - promoted by a group of former senior USA military officers, and often described as a "Marshall Plan" of sorts - would involve United States companies working with Russian companies to build and operate nuclear plants in the Middle East, and export spent fuel from those plants.
Cummings added: "They have now informed us that they have done so". Congress later passed a bipartisan measure that placed new sanctions on Russian Federation, a bill that Trump reluctantly signed in August.
"Mike has been putting everything in place for us", Copson said, according to the whistleblower.
"When the whistle-blower asked why the United States needed to be involved in a Middle East nuclear project, Mr Copson explained that the USA would provide military support to "defend these installations", the letter said.
On Friday, Flynn pleaded guilty to lying to Federal Bureau of Investigation agents about conversations he had in December 2016 with the Russian ambassador to the United States about the sanctions, among other topics.
The witness did not specify which sanctions Flynn was referring to in his texts.
As the president spoke, Flynn reportedly texted Copson that the nuclear project was "good to go", the witness said Copson told him. The subpoena to the White House should be for "all documents - including emails and text messages sent on personal devices" about Mr. Flynn's foreign contacts, payments and efforts to promote the proposal. The whistleblower saw that the time stamp of the message was 12:11 pm, but did not read the text.
One businessman involved in the project - Alex Copson of ACU Strategic Partners - even dubbed it the "Trump/Putin M.E".
Cumming also noted the congressional probe into Hillary Clinton's role in an Obama-era Uranium One deal that Gowdy is spearheading- a probe that was recently announced after Republicans said they had found a new informant.
An attorney for Copson has denied any communications between Flynn and employees of the company, ACU.
"Although this individual was extremely hesitant to come forward - and still fears retaliation - the whistleblower has made a decision to do so now because this individual feels duty bound as a citizen to make this disclosure", he wrote.
Perhaps most intriguingly of all, Cummingswrites that he told Special Counsel Robert Mueller's team about all this some time ago - and that they asked him to delay publicly revealing this information "until they completed certain investigation steps".
The Wall Street Journal reported in September that while in the White House Flynn promoted a project that would involve building dozens of nuclear plants around the Middle East.
The whistleblower, who provided his account to Cummings in June, said he was with Alex Copson, managing partner of ACU Strategic Partners, a key Flynn ally on the nuclear project, on January 20, Inauguration Day. ACU funded the travel, which Flynn failed to disclose on his security clearance renewal application in 2016 and to background check investigators. Flynn had been a paid consultant for the business venture before he joined the Trump campaign a year ago.