Two rhinoceros horns were stolen from a British museum on Saturday - only the horns were fake and worthless.
The horns were removed from a stuffed Indian rhino and a White rhino specimen at the Natural History Museum's site in Tring, northwest of London.
However, due to a recent spate of such thefts across Europe, the museum had replaced the horns with replicas.
Rhinos are often poached for their horns, made of keratin and sold on the black market for ornamental or medicinal purposes, particularly in Asia.
Horns fetch around £60,000 ($100,000, 70,000 euros) per kilogramme.
"The theft occurred around 4:00 am (0300 GMT) this morning, following a failed attempt at midnight," a Natural History Museum spokeswoman, Chloe Kembery, told AFP.
"The horns were replaced with replicas about three months ago and each horn weighs about two kilos."
A rising number of science museums in Europe are being targeted for the horns.
Europol, the European Union's criminal intelligence agency, suspects an Irish organised crime group is behind the spate of robberies that has also hit zoos, auction houses, antique dealers and private collectors across the continent.
The Tring museum was closed Saturday while the building and the displays were repaired following the break-in.
"The police have been notified of the incident and a thorough investigation of the matter is now under way," the spokeswoman said.
Earlier this month, robbers made off with two rhino horns from a Belgian museum, the third such heist in the kingdom in less than two months.
Trade in rhino horns is banned under the CITES international agreement, the 1975 Convention on International Trade in Endangered Species of Wild Fauna and Flora.