Prabhakar Sail, an independent witness, on Monday appeared before the Narcotics Control Bureau's (NCB) Delhi vigilance team and named agency's zonal director Sameer Wankhede for his involvement in the pay-off allegations in the Cordelia cruise drugs case. Advocate Tushar Khandare said that if NCB's operational team wants to question Prabhakar Sail then they first have to issue a notice.