He didn't divulge the relationship until the third version of his financial disclosure report, required of White House employees, which he filed in August.
Neither Gowdy nor Flynn's attorney, Robert Kelner, responded immediately to a request for comment. And one of the companies involved in the project covered his travel expenses and wrote him a check for $25,000 for the trip, though it's not clear if Flynn cashed the check.
After getting the texts, Copson said, "Mike has been putting everything in place for us", and, "This is going to make a lot of very wealthy people", Cummings said, quoting the witness. But the nuclear project that Flynn and his business associate had worked on together was stymied by US financial sanctions on Russian Federation.
Mr. Copson is the managing partner of ACU Strategic Partners and was working with General Flynn to promote a joint project with Russian Federation to build nuclear reactors in the Arab world.
In June, the whistleblower first contacted Cummings and gave the congressman permission to share the account as part of the ongoing investigation into Russia's meddling in the 2016 presidential election.
The letter said that if this witness account is accurate, Mr Trump's national security adviser "was trying to manipulate the course of global nuclear policy for the financial gain of his former business partners".
"Your letter seems to resort to desperate and baseless jurisdictional excuses to avoid conducting oversight in an apparent attempt to protect President Trump and his Administration", Cummings said while pointing out "inaccuracies" in Gowdy' letter.
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"Who he represents in court is Kapil Sibal's personal matter", Congress spokesperson Randeep Surjewala had said. Incidentally, it was also the 25th anniversary of the demolition of the structure in Uttar Pradesh's Ayodhya.
Cummings did not name the whistleblower in the letter, but offered to have Gowdy speak with the person directly.
With the clearance of Mueller's office, Cummings writes that he's now making the whistleblower's story public.
The company did not respond to a request for comment Wednesday.
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.
Now, Mr Cummings wrote, he and his colleagues have been authorised to to go public with the information.
Mr Copson showed his phone with the text message to the whistle-blower, who saw that the time stamp of the message was 12:11, but didn't read the text.
The Maryland Democrat said he considered "credible" the allegations that Flynn "sought to manipulate the course of global nuclear policy for the financial gain of his former business partners".
Alex Copson, the managing partner of ACU Strategic Partners, received texts from Flynn during Trump's inauguration January 20 saying the deal was "good to go", according to Cummings. Given the seriousness of the charge and the person making it, if the committee isn't going to issue a subpoena, Robert Mueller nearly certainly will.