After cracking down on drug trafficking being conducted through the 'darknet' recently, the NCB is set to freeze about 500 Bitcoins in the accounts of traffickers, the first ever seizure of the virtual, unregulated currency in a criminal probe in the country.

The central agency, the nodal department to combat drug trafficking and liaise with multiple narcotics control and enforcement agencies, has interdicted and begun investigation against three syndicates in the country till now and in one case detected in western India, it is moving to seize Bitcoins.

Official sources said the Narcotics Control Bureau (NCB) is working on the legal aspects of the case to seize about 400-500 Bitcoins as part of its criminal investigation under the Narcotic Drugs and Physchotropic Substances Act (NDPS) besides a few other laws.

"While criminal probe agencies have seized a variety of assets like cash and immovable assets in their respective investigations all these years, Bitcoins have never been frozen as part of the tainted assets seizure. Bitcoin is equivalent to about Rs 1 crore in the Indian currency. The NCB is moving in that direction," sources in the agency said.

Officials, however, declined to disclose further details about the specific case which has been referred to the NCB headquarters for vetting. The case has also been reviewed by NCB Director General R R Bhatnagar.

The case pertains to the trafficking of drugs and narcotic supplements over the cryptic form of internet called 'Darknet' using the illegal payment method of Bitcoins to thwart detection by investigative agencies.

'Darknet' refers to the clandestine internet network which can only be accessed with specific software, configurations and authorisation and is difficult to track using usual communications protocols and ports, while Bitcoin is a cryptocurrency that allows consumers to make electronic transactions by skipping the legal banking channels.

NCB officials had earlier told