NEW DELHI, Nov. 21 -- The National Investigation Agency (NIA) on Thursday formally arrested four key conspirators in the November 10 Red Fort blast taking the agency's total arrests in the case to six. All four - Dr Muzammil Shakeel Ganai of Pulwama, Dr Adeel Ahmed Rather of Anantnag, Dr Shaheen Saeed of Lucknow, and Mufti Irfan Ahmad Wagay of Shopian - had earlier been detained and subsequently arrested by the Jammu & Kashmir Police as part of the nationwide crackdown on the so-called "white-collar" terror module. Investigators believe each of them played a direct role in planning and executing the suicide attack that killed at least 12 people. The suspects were taken into custody in Srinagar on production warrants issued by a Patiala House Court judge, who also remanded them to 10 days' NIA custody on the agency's request for 15 days of custodial interrogation. A senior NIA official described the arrests as "among the most significant" since the probe was handed over to the agency shortly after the blast. "We had earlier apprehended Amir Rashid Ali - the registered owner of the car used in the explosion - and Jasir Bilal Wani alias Danish, who allegedly provided technical and logistical support to the bomber," the official said, requesting anonymity....