The dogs' skills in water searches are remarkable. A body under water emits gases and fats which rise to the surface. The dogs are capable of detecting the scents of these, no matter the depth at which the body lies. When they identify the exact point at which the traces are rising to the surface, the dogs are trained to jump into the water and swim round the spot in a circle, enabling a very precise location of the target.

Finder prepares to mark a trace.

Signi's first international mission was to Morocco in February 2004, following the earthquake there. In December of the same year came the dreadful Asian Tsunami. Saad is unlikely to forget the date of that one – his birthday is on the 23rd of December, and he was having a party to celebrate when news of the Tsunami broke.

Signi first spent a week in Sri Lanka, where they were a huge help to the local police and population, who had little in the way of resources or equipment to facilitate their work. On their return to The Netherlands they received considerable publicity, and a dog food manufacturer who had planned to make a donation to the Tsunami Appeal decided to fund a second trip for Signi instead, and sent them to Thailand.

In August 2005 they were in the USA following Hurricane Katrina, although Saad's memories of that visit are mixed. "It was very bureaucratic. To be honest, I spent most of my week there trying to sort out paperwork, although Esther and Janette stayed on for a second week and were able to provide some help."

Finally, there was the earthquake in Pakistan in October of 2005. The Pakistani Army and Police were deeply impressed by the work of the Signi dogs, who on their first assignment were able to identify the location of 11 victims buried by the quake.