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