In Malaysia’s illegal crypto mining hotspots, the hunt begins in the sky.

Drones buzz over rows of shops and abandoned houses, sweeping for pockets of unexpected heat, the thermal signature of machines that shouldn’t be running. On the ground, police carry handheld sensors that sniff out irregular power use. Sometimes the pursuit is more low-tech: residents call in with complaints of strange bird noises, only for officers to discover nature sounds being used to mask the roar of machinery behind closed doors.