Kochi: The source of the recent 2-tonne drug haul by the Narcotics Control Bureau (NCB) and Indian Navy in Indian waters has been traced to a Pakistan-based drug mafia led by Haji Salim, NCB sources said on Saturday.

The catch – methamphetamine or crystal meth - found carefully packed in 134 plastic bags – weighed 2,525 tonnes, the source said. It costs Rs 25,000 crore in the market, according to the source.

The NCB had on Saturday said the substance cost approximately Rs 15,000 crore in their preliminary assessment. The agency revised its valuation as the contraband was found to be of ‘very superior quality’, an officer said.

The origin of the consignment has been traced to Jiwani port in the Baluchistan province of Pakistan, according to the NCB. The bureau detained a suspected Pakistani national during the operation which led to the massive seizure. He was being questioned by the agency; the suspect would be produced before a local court at Mattancherry in Kochi on Monday.

The seized packets were brought to Mattancherry wharf on Saturday.

The Navy and the NCB seized the drug consignment from a vessel, which the agencies call 'Mother Ship', from an undisclosed location in the Indian waters. It is still not clear what happened to the ship. NCB officials, on the condition of anonymity, said those who were on board the vessel managed to sink it before escaping.

The Navy launched a search to trace the members of the racket who managed to flee from the ship and recover the stock which they jettisoned in the sea.

According to media reports, the drug trafficking gang tried to sink the ship when they realised NCB and Navy officials were in pursuit. After capsizing the vessel, the gang members took boats and managed to flee from the spot. Navy officials detained the Pakistani national after chasing one of these boats.

The NCB officials said Saturday's seizure was the biggest haul of methamphetamine (crystal meth) in the country in terms of monetary value.

The NCB and Navy launched a joint operation to seize drugs from the vessel after receiving a tip-off on traffickers in Indian waters.

The officials confirmed that three labs in Pakistan produced the substance.

"Three different symbols were found on the sacks used to pack the contraband. So, it was confirmed that drugs were produced in three labs. The packaging was also cleverly done to preserve it in the sea,” said the officials.