>> i have done absolutely nothing wrong and that's why i have been fully cooperating. >> reporter: f.b.i. agents confronted the three-time master's champion at a tournament in dublin ohio. the f.b.i. and s.e.c. are reportedly looking at two others, billionaire investor carl icahn and sports bettor billy walters who was profiled by "60 minutes" in 2011 and is said to be mickelson's friend and golf partner. michael rothfeld is a reporter for the "wall street journal" who broke the story. what first caught the eye on investigators? >> there was suspicious trading in clorox which is a company carl icahn took a big stake in and actually made a big offer for. >> reporter: the journal reports in july of 2011, days before icahn launched that offer, large trades in clorox options were made. once icahn made the bid the options rose. the papers says regulators traced the suspicious trades back to mickelson and walters and are now trying to figure out if icahn tipped off walters about his buy out...