When the phone rang at about 3am on April 18, Nigel Monaghan was asleep on the floor in his office in Dublin, tangled in a sleeping bag. As keeper of the National Museum of Ireland's natural history section, he was overseeing filming of a children's TV special, 'Sleepover Safari'.
Ten children, their parents, and a film crew were spending the night in the museum, known locally as the Dead Zoo, surrounded by Ireland's foremost collection of taxidermy.
The call was from the museum's central security office.
Four stuffed rhino heads that Monaghan had sent away for safekeeping a year earlier had been stolen from the museum's storage facility near the airport.
At 10.40pm, three masked men forced their way in, tied up the guard on duty, and found the shelves where the heads were kept. The trophies were heavy and awkward. Expertly stuffed and mounted by big game taxidermists at the turn of the 20th Century, they were monstrous confections of skin and bone, plaster and timber, horsehair and straw.
When Monaghan and his team had come to move the largest -- that of a white rhino shot in Sudan in 1914, with a horn more than three feet long -- it had taken four men just to lift it down from the museum wall. But the burglars were undeterred and soon they had every head in the back of their white van. They took nothing else, and within an hour they were gone.
Monaghan couldn't go back to sleep. He turned on the office lights, sat at his computer, and began writing a press release.
It seemed the Rathkeale Rovers had struck again.
Rhino horn is one of the world's most valuable illegal commodities, part of an international trade in endangered species estimated to be worth $10bn (€7.3bn) a year, according to Global Financial Integrity, a research organisation that tracks underground commerce.
Over the last century, rhinos have been hunted to the brink of extinction, and traffic in rhino products is now regulated by the Convention on International Trade in Endangered Species, or CITES. In Asia, powdered rhino horn has long been a valued part of traditional medicine.
It's recently become more prized by a new capitalist elite in Vietnam -- where it's mixed with wine at parties, an emblem of conspicuous consumption -- and China.
Word of the fortune hidden in rhino horns spread quietly at first. For years, horns mounted before 1947 were exempt from the export regulations of CITES and could be legally exported from Europe.
But in 2006 antique horns began achieving unprecedented prices at auction; over three years their cost rose ten-fold.
In 2010, after a single horn sold at British auction for a world record £99,300 (€119,405), European authorities announced an export ban on antique rhino trophies.
The first signs of an Irish connection in the world of rhino horn trafficking went almost unnoticed. In January 2010 customs officers at Ireland's Shannon Airport confiscated eight horns from the baggage of two passengers on a flight from Faro, Portugal. Officials weren't even certain a crime had been committed; they had never seized a rhino horn before. No arrests were immediately made, and the evidence was sent to Dublin Zoo for analysis.
The passengers were two Irish brothers who said they were travelling antique dealers who spent most of their time living in French and German caravan parks.
Across the Atlantic, the United States Fish and Wildlife Service also began hearing strange complaints about Irishmen attempting to purchase rhino horns illegally.
By the beginning of November 2010, working at Europol headquarters in the Hague, the Irish police force's liaison for Interpol, John Reid, had spent several months collecting and analysing intelligence from across Europe.
With help from detectives of Dublin's Criminal Assets Bureau (CAB) he assembled a detailed briefing on a criminal group that had come to be known as the Rathkeale Rovers.
The Rovers have been of interest to the CAB for much of the last decade but have proved hard to prosecute -- not least because they rarely seem to commit any crimes in Ireland. Unlike a conventional criminal gang, set up and directed to accomplish a single illegal enterprise, the Rathkeale Rovers operate within the extended families of the Irish Traveller network.
In November 2010, Reid convened a meeting in the Hague with Europol intelligence analysts and fellow liaison officers from a dozen member states.
He explained how the rash of crimes they had been reporting all originated with a single criminal network; and for the first time he revealed their involvement in the illegal rhino horn trade.
As a result of the meeting, the Rathkeale Rovers became the target of a pan-European investigation designated Operation Oakleaf.
In the wake of Operation, the epidemic of rhino horn burglaries in Europe has subsided, and those taken from the Natural History Museum of Ireland's storage facility last April are among the last to have been reported stolen.
Those heads have not been recovered, and no arrests have been made, but authorities say they have little doubt the Rovers are responsible.
The thefts have slowed partly because museum curators, now more aware of the horns' value, have removed them from display or replaced them with resin replicas.
With even the stuffed animals in the Dead Zoo hunted to extinction, the Rathkeale Rovers have turned to the quest for another rare commodity. Recently, security guards at the Chester Beatty Library at Dublin Castle reported a visitor who seemed especially interested in its collection of antique Chinese jade. He didn't much resemble the other whispering aesthetes examining the library's renowned Eastern treasures, but he took a few pictures with his iPhone. Soon after he left, the museum curators took the precaution of removing every last piece of jade from display. (Bloomberg)