The National Investigation Agency said on Tuesday that it has arrested an Afghan national in connection with the seizure of heroin worth Rs 21,000 crore at Gujarat’s Mundra Port in September.

Nearly three tonnes of heroin, disguised as a consignment of semi-processed talc stones, had arrived from Afghanistan through Iran’s Bandar Abbas port.

The consignment had been seized by the Directorate of Revenue Intelligence. It was reported to be India’s biggest drug haul so far.

Eight people, including four Afghans, one Uzbek and three Indians were arrested in connection with the case, the government had said on September 22.

In October, the National Investigation agency took over the case. The authorities are looking into a narco-terror link in the case, the Hindustan Times reported.

After taking over the investigation, the agency filed a case against the accused persons under the Unlawful Activities Prevention Act.

In a press note on Tuesday, the National Investigation Agency said it had arrested an Afghan national who was “involved in the conspiracy of transporting narcotic drugs”. The 28-year-old man lived in South Delhi.

A case has been filed against the man under sections of UAPA, the Narcotic Drugs and Psychotropic Substances Act and the Indian Penal Code.

Before this, the National Investigation Agency had arrested seven accused persons in this case. “Further investigation in the case continues,” the agency added.