A man demonstrating how to make a home-made bomb
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Hunting down down terrorists by monitoring sewers

New technology allows security services to analyse the contents of the sewers to discover where people are making home-made bombs.

The new system is being tested in Sweden and will make it possible to check for the substances which may be by-products of bomb-making.

Many recent attacks, including those in Boston, London and Madrid, have been the result of 'home-grown' terrorism, and this could help reduce the risks of more bombings.

Rebecca Morelle reports from Stockholm.

  • 30 Sep 2014
  • From the section Europe
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