ROTTERDAM, Netherlands - The latest species to join Dutch police is hard at work behind the blacked-out windows of a building in Rotterdam: rats learning to sniff out crime and a new forensic future.
Derrick, Thomson and Thompson, Magnum and Poirot, all named after fictional detectives, are being groomed to help police not only keep the streets clean but also save time and money.
"As far as we know we're the first in the world to train rats to be used in police investigations," said Mark Wiebes, who heads the Dutch police "innovation" centre.
Each rat costs just 10 euros (around S$16) and can, in theory, be taught to identify any odour, from drugs to gunpowder, while a sniffer dog costs tens of thousands of euros to buy and train.
A police dog's training also takes around eight months, although once completed the dog's abilities are far greater than a rat's.
The rats have been living in a cage inside a small prefab building since late 2011, alongside more grandiose buildings and grounds where police dogs and horses are trained.
The rats learn quickly in the darkness the nocturnal rodents prefer.
"They need barely 10 to 15 days to learn to distinguish a certain smell," the policewoman in charge of the project, Monique Hamerslag, told AFP, lifting Derrick out of his large cage and into a smaller one where he will be put to work.
"The more boring a rat's life is, the better" it is at detective work, said Hamerslag, who also discovered that male rats are better at the job than female rats.