Shares of Russian steelmaker Evraz, whose controlling shareholder is Roman Abramovich, slipped this morning on a Russian business news agency's report that the Russian billionaire was being detained by the FBI.
Shortly after 9 a.m. E.T. this morning, Russian news outlet RBC.com Tweeted that Abramovich had been detained in the U.S.
Via Google Translate the Tweet says, "Lightning! In the U.S., detained Roman Abramovich. Details soon." 
Minutes later, RBC.com posted a story on its site.  Then Russia Today Tweeted the report. 
A spokesperson for Abramovich John Mann Tweeted that the RBC story is "NOT TRUE."
The FBI declined to comment. 
RBC's report appeared to move Evraz's stock though.  Check out the chart from Yahoo! Finance.  The stock, which is traded on the London Stock Exchange, tanked right after 1 p.m. GMT, which would be right after 9 a.m. ET when the report first surfaced. 
Evraz chart
Yahoo! Finance