The photo was taken from the north-east corner of your bedroom. There is a ventilation grille there, twenty centimetres across, accessible from the service corridor behind the building. Someone placed a camera through it, remotely triggered, and retrieved it before morning — or left it there.
You take a kitchen knife, go back to the bedroom, and unscrew the grille. Inside, a small black lens no larger than a fingertip, still warm. It transmits via Bluetooth. The signal has a device ID.
You are not supposed to know how to trace that. But you spent eleven years knowing things you were not supposed to know.
You open your laptop, pull up a network scanner, and begin.
What happens next?
1 Trace the Bluetooth device ID