India, April 11 -- The National Investigation Agency (NIA) on Friday secured 18-day custody of Tahawwur Hussain Rana, a key accused in the 26/11 Mumbai terror attacks, following his extradition from the United States. The agency aims to interrogate Rana in-depth to unearth the entire conspiracy behind the brutal 2008 attacks that left 166 dead and over 238 injured.

Rana was produced before the NIA Special Court at Patiala House in New Delhi after his arrival at the Indira Gandhi International Airport on Thursday evening. He was formally arrested and later escorted under heavy security-led by Delhi Police SWAT teams-to the NIA headquarters at the CGO Complex, where he will remain in a high-security cell.

In a statement, the NIA said Rana...