India's anti-narcotics agency has given a clean chit to Bollywood superstar Shah Rukh Khan's son Aryan in the drugs-on-cruise case.

Aryan (23) and his two friends -- Arbaz Merchant and Mummun Dhamecha -- were among 20 people arrested by the Narcotics Control Bureau (NCB) on October 3 last year in connection with a rave party the agency "busted" on board a cruise ship off Mumbai coast a day before.

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On Friday, the NCB dropped all charges against Aryan, claiming that no drugs were found on him during the raid, and five other accused "for lack of evidence". However, the agency, in its chargesheet filed in the court, named 14 others in the case.

"There were indeed some irregularities in the initial probe. Action will be taken against the officials concerned for the lapses," NCB chief SN Pradhan told the media.

In fact, on the evening of October 2, some 30 NCB sleuths, disguised as passengers, boarded luxury cruise liner 'Empress' which departed Mumbai port for the neighbouring coastal state of Goa.

The cruise ship was carrying mostly celebrities from Bollywood and the fashion industry. As soon as the rave party began later that evening, the NCB sleuths swung into action and claimed to have caught red-handed those having drugs.

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Aryan, his two friends, and seven others were soon detained. While two of the detainees were freed after questioning, the NCB sleuths placed Aryan and seven others under arrest a day later after over 12 hours of interrogation. Aryan got bail from a court on October 28.

Aryan's father Shah Rukh is considered the most talented Bollywood star. Popularly called "King Khan", he has acted in over 80 films in a career spanning over 25 years. And he has a net worth of USD 700 million.