Former President Supreme Court Bar Association (SCBA), Aitzaz Ahsan has said that the government has no option but to write a letter for opening of Swiss cases on the orders of the Supreme Court. Talking to media men here on Wednesday, the former President SCBA said President Asif Ali Zardari is enjoying the immunity as he is the President of the country. On return of former President Pervez Musharraf, Aitzaz Ahsan said that he (Musharraf) has no courage to return to Pakistan as he has to face charges against him and mentioned the May 12 incident and murder of Nawab Akbar Bugti. Responding to a question, the former President SCBA observed that if the incumbent government of PPP failed to expose murderers of Benazir Bhutto, then it would be impossible for PPP to come into power again. He said that the report of the United Nations regarding the assassination of Benazir Bhutto has flaws and questioned who had ordered Saud Aziz to wash out evidences. Commenting on massacre on May 12, Aitzaz Ahsan said that workers of PPP and ANP were murdered on the day and both parties are in power and the responsible could not bring to justice as people involved in the massacre also in power.