"The new allegations appear to stem from what Nissan has described as an 'ongoing' investigation into potential financial improprieties. But that project has itself proved highly controversial. In January, Carlos Munoz, the former head of Nissan’s North American operations, resigned in a dispute over the effort. Toshiyuki Shiga, former Nissan Chief Operating Officer, who had continued serving on the Nissan board, also tendered his resignation, privately raising concerns over the handling of the Ghosn case."