New Delhi, Oct 25 (PTI) Sameer Wankhede, the Narcotics Control Bureau"s Mumbai zonal head who is leading the probe in the cruise drugs case in which actor Shah Rukh Khan"s son Aryan Khan is arrested, arrived in the national capital on Monday night. His visit to Delhi comes in the backdrop of the NCB ordering a vigilance inquiry into the allegations made by a witness in the cruise drugs case of an extortion bid of Rs 25 crore by some agency officials, including Wankhede, and others for letting off Aryan Khan. The officer told media persons outside the Indira Gandhi International Airport here that he has not been summoned by the agency but has some work here. The officer on Sunday had written to Mumbai Police commissioner Hemant Nagrale, seeking protection from likely legal action "being planned" against him by unknown persons to falsely frame him concerning an alleged vigilance-related issue. Wankhede on Monday failed to get any relief related to an affidavit on the sensational extortion claims made by the independent witness, Prabhakar Sail, with a special court saying it cannot pass a blanket order barring courts from taking cognisance of the document. PTI NES RT RT