to look for links to Russian money.
Special Counsel Robert Mueller is questioning Russian oligarchs over their alleged donations to the 2016 Trump campaign.
Special Counsel Robert Mueller's investigation team in the Russia probe is questioning Russian oligarchs; some sources say that sanctions might be introduced this week, United States media reported. It was unclear if he had his devices scanned.
Mueller's team is seeking to find out if wealthy Russians illegally funnelled cash donations directly or indirectly to the Trump campaign.
The Mueller team made an informal voluntary document and interview request to a third Russian oligarch who has not visited the United States, the report said.
The revelation signals that Mueller is aggressively exploring a broad range of angles into whether there was any type of coordination between the Russian government and Trump's campaign.
White House counsel Ty Cobb, who's coordinating the administration's response to the Mueller probe, said the development was news to him.
Mueller reportedly stopped two Russians when they traveled to the US and searched one's electronic devices. But Mueller's office has not previously revealed an interest in speaking with Russian oligarchs directly.
CNN learned that investigators are interested in links between Russians and think tanks or companies that have political action committees that may have donated to the president's campaign.
Wealthy business leaders in Russian Federation often operate at the Kremlin's behest or, at the very least, with its blessing.