 These included the Head of Human Resources and the Company Secretary.On 23 April Mehmet Dalman, the chairman of ENRC, also resigned and next day the group confirmed that Gerhard Ammann, a non-executive director of ENRC and president of Bank Von Roll, a Swiss private bank, would replace Mr Dalman.The Serious Fraud Office launched a criminal investigation into ENRC's business practices in April 2013.