Reza Zarrab, the star witness unnerving Ankara

It’s a case that has captivated Turkey and rattled Ankara: Reza Zarrab has become the star witness in a New York trial over alleged subversion of US economic sanctions against Iran, implicating a former Turkish minister and President Recep Tayyip Erdogan. The Turkish-Iranian gold trader — who was arrested in March 2016 en route to a…