Around 200 rare books worth more than £2.5 million are thought to have been stolen from a London warehouse by a shadowy Romanian mafia gang in a daring Mission Impossible-style heist.
Works from the 17th century by Sir Isaac Newton, Italian astronomer Galileo and the 18th century Spanish painter Francisco Goya, were stolen from a facility in Feltham, where they were being stored before being sent to Las Vegas for a specialist book auction.
The antiquarian collection has been deemed of international cultural importance and is considered irreplaceable, police said.
The collection included a 1566 copy of De revolutionibus orbium coelestium by astronomer Nicolaus Copernicus, worth an estimated £215,000.
There were also works by some of the most important early printers, including editions of Aesop’s Fables (1505) and the tragedies of the Greek playwright Euripides, printed in 1503 in Venice by Aldus Manutius.
The haul was taken in what police described as a "highly sophisticated burglary" in January 2017, when the books were in storage at the postal transit warehouse.
Two thieves broke in by cutting holes in the roof, then abseiling down and perching on shelves to avoid the many sensors that would have set off the alarms.
In a five-hour operation, the books were then loaded into 16 large bags before the gang left in the same way it had entered at 2.15am, Scotland Yard said.
The books, which belonged to three separate book dealers, were stored at a rented house in Balham, South London, before being smuggled out of the country via the Channel Tunnel.
The police investigation prompted suspicions that a feared Romanian mafia group called the Clamparu, which was behind a string of high-value warehouse burglaries across the UK, could be involved.
The organised crime gang (OCG) flies members into the UK to commit specific crimes and then flies them out of the country shortly afterwards, with the stolen property removed from the country by other OCG members using different transport methods.
Scotland Yard said the OCG is linked to a number of prominent Romanian crime families who form part of the Clamparu crime group.
The group is based in the Iași region in Eastern Romania, and has a history of complex and large-scale high value thefts, yet has largely avoided prosecution as its crimes take place outside Romania.
An international manhunt for the book thieves involved the Metropolitan Police, the Romanian National Police and the Italian Carabinieri, along with Europol and Eurojust.
It took more than three years to track down the books, which included a rare edition of Newton’s Principia, down to a rural location in Neamt, north-east Romania, where they were discovered in neatly wrapped packages stashed under floorboards.
A series of police raids led them to the find on Wednesday.
Detective Inspector Andy Durham, from the Met Police's Specialist Crime South, said: "This recovery is a perfect end to this operation and is a demonstration of successful joint working between the Met and our European law enforcement partners in Romania and Italy - and at Europol and Eurojust.
"These books are extremely valuable, but more importantly they are irreplaceable and are of great importance to international cultural heritage.
"If it wasn't for the hard work of Detective Constable David Ward and others in this Joint Investigation, Team these books would have been sadly lost to the world forever."
Thirteen suspects were charged in the UK with conspiring to commit burglaries between December 2016 and April 2019, and to receive criminal property.
Court proceedings are ongoing, with 12 individuals having already pleaded guilty and sentencing is due to take place over four days, beginning on September 28.
The thirteenth defendant will be tried in March 2021.