Flynn is the first person in the Trump administration to be investigated.
Flynn, a retired lieutenant general who served as a military adviser to Trump during the campaign, will have a crucial role in shaping US policy toward Russian Federation.
Hours after retired army general Michael Flynn was sworn in as national security advisor on Sunday, the Wall Street Journal reported that Flynn's communication with Russian officials have been-and possibly still are-under investigation by USA intelligence agencies.
The probe is part of a counterintelligence investigation into Russia's activities such as cyber attacks in the U.S.
News added later in the day that the FBI is not only part of a multi-agency investigation into Russia's alleged intervention in the American presidential campaign, but us officials are also "examining how the operation was paid for and whether any Americans were involved".
The Journal, citing sources, said it was not clear if the counterintelligence inquiry produced any incriminating evidence or if it is continuing. While Manafort, Page, and Stone played key roles in Trump's campaign operation, none of them has an official role in the White House now.
Federal Bureau of Investigation and intelligence officials briefed members of the Obama White House team before President Barack Obama left office about the Flynn calls to the Russian ambassador, sources said.
Some backstory is probably in order.
Retired Lieutenant General Michael Flynn at the White House for his swearing in ceremony.
Flynn ties to Russian Federation date back to at least 2014 when he made several appearances on Russia's state-run television network RT after departing the Defense Intelligence Agency.
Flynn came under scrutiny earlier this month after reports surfaced that he had phoned the Russian ambassador to the USA on the same day President Obama expelled 35 Russian diplomats in response to the Kremlin's reported election hacking. The Logan Act (though never enforced) bars US citizens from correspondence intending to influence a foreign government about "disputes" with the United States.
Investigators collected communications during the course of the presidential campaign between people believed to be intermediaries of the Russian government and Trump surrogates and others associated with the president's 2016 election campaign.
White House Press Secretary Sean Spicer has previously explained that Flynn's calls with Kislyak were for the objective of setting up talks between Trump and Vladimir Putin after Trump's inauguration.