Flynn received tens of thousands of dollars from Russian companies in 2015, just before he became a top surrogate to Trump and well before his brief stint in the USA government, The Wall Street Journal reports, citing documents obtained by Congress.
He also received a similar amount from a cybersecurity company in Russian Federation that was looking to expand its business with the US government, the newspaper reported.
The same amount also was given to Flynn from Kaspersky Government Security Solutions, the subsidiary of a major Russian cybersecurity firm with ties to the country's intelligence community.
"I'm not a G2 guy, but I feel like I'd remember receiving "$68,000 in fees and expenses from Russia-related entities in 2015", including $11,250 from a cybersecurity firm rumored to be connected to USA election hacking.
"I can not recall any time in our nation's history when the President selected as his National Security Advisor someone who violated the Constitution by accepting tens of thousands of dollars from an agent of a global adversary that attacked our democracy", Rep. Elijah Cummings (D-Md.), the top Democrat on the House Oversight Committee, wrote in the letter to the Trump administration.
In the letter, Cummings accused Flynn of violating the emoluments clause as it pertains to military regulations that prohibit retired military officers from receiving payments from a foreign government.
The newly-released files show that RT - designated by the USA intelligence community as a propaganda arm for Russia's government - also paid for luxury hotel stays and other expenses incurred by Flynn and his adult son, Michael Flynn Jr., during the Moscow trip.
Flynn resigned as Trump's national security adviser in February, amid controversy over his characterization of discussions he had with Russian ambassador Sergey Kislyak in December.
Flynn, a retired military general, stepped down as President Trump's national security advisor after revelations about his ties to Russian Federation. Flynn, who retired from active duty in 2015, shared a table with Russian president Vladimir Putin at the gala, which was held in Moscow.
Both came about a "year after he had been fired as director of the Defense Intelligence Agency and while he continued to maintain a top-secret level security clearance", the Journal noted. Documents released in a congressional inquiry show Flynn was paid more than $33,750 by RT, Russia's government-run television system, for appearing at a Moscow event in December 2015.
Flynn went on a three-day trip with his son, Michael Flynn Jr., staying in a five-star hotel at the Russian government's expense for RT's 10th anniversary celebration in 2015, according to Yahoo. An attorney for Flynn revealed that before Trump's inauguration, the transition team was informed that Flynn was considering filing as a foreign agent with the Department of Justice to comply with the Foreign Agent Registration Act.
The documents filed with the Justice Department showed that Flynn Intel was working on a project of great interest to the Turkish government.
After the election Trump named him White House national security advisor - only to have to ask for his resignation weeks later amid a storm over his calls with the Russian ambassador.