Prabhakar Sail, an independent witness, was questioned for more than 10 hours by the NCB's Delhi vigilance team, probing the pay-off allegations in the cruise drugs case in which actor Shah Rukh Khan's son Aryan Khan is an accused, an NCB official said on Tuesday.

He has been called by the anti-drugs agency again on Tuesday, the official said.

Earlier, after being summoned by the NCB on Sunday, Sail along with his lawyer reached the Central Reserve Police Force's (CRPF) mess in suburban Bandra under police protection at 2 pm on Monday.

He left the place, where the NCB team questioned him, around 12.20 am on Tuesday with his lawyer and did not speak to media persons present outside the premises.

"We have called him again for questioning on Tuesday, NCB's Deputy Director General (northern region) Gyaneshwar Singh said.

The NCB's vigilance team, headed by Singh, who is also chief vigilance officer (CVO) of the federal anti-narcotics agency, had reached here from Delhi on Monday morning.

Sail, who claims to be the bodyguard of NCB witness KP Gosavi, last month alleged in an affidavit that he had heard Gosavi discussing a Rs 25 crore pay-off deal after Aryan Khan was arrested by the NCB.

Sail claimed that Gosavi had said Rs 8 crore of the deal money was to be given to NCB's Mumbai zonal director Sameer Wankhede.

Sail's allegations had prompted the NCB to order a vigilance inquiry against NCB officials and others.

Wankhede had denied the allegations against him.

Last month, a vigilance team led by Singh came to Mumbai to probe the allegations of extortion, but had then failed to record Sail's statement.

It had at that time recorded statements of eight persons, including Wankhede, and collected some important documents and recordings related to the cruise drugs case, an official earlier said.