Delhi/IBNS, Nov. 15 -- The investigation into the November 10 Red Fort blast, which killed 13 people and injured several others, has taken a striking turn.

Delhi Police sources say the accused were using a covert digital communication method long associated with espionage networks - 'dead drop' emails, a system designed to bypass surveillance and leave almost no trace.

Instead of sending messages, the suspects allegedly used a shared email account where instructions were typed and stored only as drafts.

Others accessed the same account, read the text, modified plans, or deleted drafts - all without a single email ever being transmitted.

As no messages were sent or received, the communication generated minimal metadata, making it extre...