Fake bomb detectors 'incredibly dangerous'
Det Con Joanne Law shows the BBC's Caroline Hawley how fake bomb detectors produced by Joan and Sam Tree were meant to work.
The couple made the Alpha 6 device in their garden shed in Dunstable, in Bedfordshire.
The City of London Police's Overseas Anti-Corruption Unit, which led the investigation, says the Alpha 6 was sold to police and security services around the world.
