Executive ready to speak out for the first time. I had a moral conflict that was really big. Reporter but our investigation took a very surprising turn. Reporter you tried to hide this from people, why did you do that . Announcer nightline will return in a moment. Good evening. Thank you for joining us. You may have heard about the company herbalife, that sells diet products through an army of nearly 3 million distributors. A huge business that has also create aid huge controversy with high profile supporters and detractors, doubling down. Now, abcs chief investigative correspondent brian ross with details of our undercover investigation. Good evening, brian. Reporter good evening, dan. We spent six months trying to learn all we could about this company which is now the target of federal investigations and the subject of an epic battle between wall street billionaires. Ladies and gentlemen, welcome to the 2013 herbalife extravagan extravaganza. Reporter the American Dream seems alive a