This week saw the official unveiling of the National Hi-Tech Crime Unit (NHTCU) which, as its name suggests, will specialise in the investigation of crimes that involve net and computertechnology.
Its reaction with the odour molecules changes a detector's electrical resistance, and this signal is fed into a neural net (the closest that computertechnology has got to imitating the pattern-recognising abilities of networks of nerve cells) to work out what is being smelt.