Amsterdam - Ten brown rats have been recruited by Dutch police to help forensic firearms experts sniff out gunshot residue.
The rats have a highly developed sense of smell, and are easier and cheaper to train than dogs, said force spokesperson Ed Kraszewski on Thursday.
"If we have a suspect, the forensic expert takes the residue from the hands and the rats can tell in a few seconds if it's from a gun," he told Reuters.
Officers place the sample behind one of a number of holes in a box. When the rat scratches at the right hole, the experts send the residue off for a final check in a lab, he added.
Rats are already used in some countries to sniff for landmines.