Dunstable couple guilty of bomb detector fraud Published duration 1 August 2014

media caption "They were actually just made from black plastic boxes, with bits of glue, bits of paper and an antenna stuck on top", reports Lisa Hampele

A couple in their sixties who made fake bomb detectors and sold them around the world have been convicted of fraud.

Sam Tree and his wife, Joan, made the bogus devices in their garden shed at Dunstable in Bedfordshire.

The couple had denied fraud at the Old Bailey trial, claiming their device, sold as Alpha 6, did work.

Each device cost just a few pounds to make using a plastic box and antenna, but they were sold for as much as £1,171 ($2,000).

Madeleine McCann

It consisted of an aerial on a handle into which a card was slotted. The card was supposedly programmed to detect different substances.

The couple, of Houghton Road, also claimed the device could help police find missing child Madeleine McCann.

The detectors were marketed by the couple's company Keygrove and some were found to have bits of torn-up paper inside, including a photo of missing Madeleine.

Prosecutor Sarah Whitehouse QC said: "The impression given is one of sophistication and effectiveness based upon scientific principles.

"Despite the fact that these plastic boxes plainly could not work, people did, astonishingly, buy them."

The City of London Police's Overseas Anti-Corruption Unit, which led the investigation, said Alpha 6 was sold to police and security services around the world.

Det Con Joanne Law said: "Sam and Joan Tree are criminals who put lives at risk when they chose to cash in on detectors manufactured to supposedly locate anything from hidden explosives to missing persons.

"The reality is the devices were absolutely useless and put both the users and the people they were bought to help and protect in grave danger."

The couple are due to be sentenced next month and Judge Richard Marks QC said: "The strong likelihood given the offence of which you have been found guilty is a custodial sentence."