Delhi Red Fort blast suspects used Swiss app Threema to plan attack: What is it and how it helped them stay hidden

The investigation into the Red Fort car blast has put a little-known Swiss messaging app called Threema in the spotlight. Police say the three doctors accused of planning the attack stayed in touch almost entirely through this app. So what is Threema, and why would someone choose it over regular platforms like WhatsApp or Signal? Here is a simple breakdown.

Threema is a secure messaging app created in Switzerland. Unlike most chat apps, it doesn’t ask for a phone number or email address when you sign up. You don’t even need a SIM card. Instead, the app gives every user a random ID, which becomes their identity inside the platform. This makes it very difficult to trace who is behind an account unless they reveal it themselves.

That is one of the main reasons investigators believe the suspects relied on it. Because no number is linked to the profile, tracking digital footprints becomes harder. Threema also offers strong end-to-end encryption. In simple words, this means only the sender and receiver can read the messages. Even the company that runs the app cannot access them.

Another feature that stands out is that Threema can be run on private servers. This is not common among messaging apps. According to police, the suspects may have set up their own private Threema server to communicate away from public networks. If true, this would allow them to share maps, documents and layouts with an extra layer of secrecy, making it nearly impossible for outsiders to intercept.