New Delhi, One of the Nirbhaya death row convicts, Mukesh Kumar Singh, on Friday, moved the Supreme Court seeking its direction and permission to file fresh curative & mercy plea. A day after the death warrant was issued by a Patiala House Court for the execution of all the four death row convicts on March 20 at 0530 hrs, defence reportedly now tried a new delay tactic. Advocate Manohar Lal Sharma moved the petition in Apex Court claiming Vrinda Grover (amicus appointed by lower court) had forced Mukesh ( now his client) to sign vakalatnama for filing curative ( later dismissed) . Now he seeks permission from the top court to file fresh curative and mercy plea.He also sought a Central Bureau of Investigation probe against Grover for "professional misconduct". The 23-year-old physiotherapy intern, who came to be known as Nirbhaya ,was gang raped and savagely assaulted in a moving bus in South Delhi area on December 16, 2012, and died fortnight later. Mukesh Kumar Singh (32), Pawan Gupta, Vinay Kumar Sharma (26) and Akshay Singh (31) were ordered to be hanged on March 20, 0530 hrs.