U.S. probed Mt. Gox CEO as possible Silk Road mastermind - agent

By Nate Raymond NEW YORK (Reuters) - A U.S. agent investigating Silk Road told jurors at a trial of accused operator Ross Ulbricht that he believed in 2013 that the former chief of the Mt. Gox bitcoin exchange, Mark Karpeles, may have been the mastermind behind the black market website. Questioning of Jared Der-Yeghiayan, a U.S. Department of Homeland Security special agent, showed Ulbricht's defence was seeking to cast doubts over the allegation that Ulbricht was Silk Road's operator,