UK—They are believed to be using Internet mapping systems to identify gardens with ponds so they can take the sought-after specimens.
Twelve thefts of the exotic fish and pond equipment, some of which are worth hundreds of pounds, have been reported over a three-week period across Hull, East Yorks.
Humberside Police Community Support Officer Sam Gregory said all the evidence suggests the culprits are using the Internet to seek out their targets.
Google Earth provides satellite photos detailed enough to see what is in people's back gardens.
PCSO Gregory said: "Google shows what is in your garden and you can see people's ponds.
"One of the properties targeted has an eight foot fence and is set back from the road.
"The pond is in the corner and can't be seen.
"Unless you were standing right next to the wall, you wouldn't be able to hear the running water."
Robert Barnes lost four koi carp and expensive lilies from his pond. The 65 year-old said: "They took the smaller fish, probably because they last longer out of the water.
"My neighbor later told me she had seen two young men with a bike with a box on it and a big black net."
Nigel Dawson, 40, woke up one morning to find his expensive filter system and 13 koi carp had been taken from his back garden.
He said: "I am devastated. I didn't see or hear anything."
A spokesperson for Google said the search engine was just one provider of such satellite images.
They said: "Google Earth is built from information that is available worldwide from a wide range of both commercial and public sources.
"As such, Google Earth creates no appreciable increase in security risks, given the wide commercial availability of high-resolution satellite and aerial imagery of every country in the world.
"Criminals could use maps, phones and getaway cars but no one would argue that these technologies are responsible for the crime itself, that responsibility lies with the perpetrator.
Article and Images Courtesy of Telegraph Media Group