Rohit and his roommate, Suman Kumar, both 23 and from Bihar’s Madhepur district, had heard about the hoax bomb threats to government offices and private schools across Delhi. The two decided to alert the police. (Photo generated using AI)

On Tuesday night, Rohit Kumar was lying on his bed, scrolling through his phone, at his paying guest accommodation — a derelict Lower Income group (LIG) building — in Mukherjee Nagar, one of Delhi’s coaching hubs.

He received a call from an unknown number.

When he picked up, the caller greeted him with “Assalam Walekum” and, in a deep, husky voice, claimed to be calling from Lahore.…