RHINOCEROS horns stolen from the National Museum during an armed raid were not insured.
Four heads with eight horns, worth €500,000, were stolen from a storage facility in Swords, Co Dublin, late on Wednesday night and are probably destined for the Far East.
Three masked men broke into the National Museum's Collections Resource Centre (CRC) on the Balheary Road at about 10.40pm and tied up a security man before fleeing an hour later in a white van.
The security guard was not injured and later managed to free himself and alert the gardai shortly after midnight.
The heads had been taken out of public display more than a year ago and put into storage after a spate of similar thefts from museums across Europe.
The rhinoceros horns were up to 100 years old and were probably stolen to supply the illegal trade in powdered horn that is used in traditional medicines in the Far East.
The gardai sealed off the premises to carry out a technical examination, and an incident room has been set up at Swords garda station.
CCTV footage is being examined as part of the probe.
Keeper with the National Museum, Nigel Monaghan, said last night the horns, which were on display on Merrion Street, were removed more than a year ago amid security concerns.
"We took a decision a couple of years ago, largely on garda advice and also from monitoring the traffic internationally, following a steady rise of theft of rhino horn. The pattern was to smash and grab, even when the museums were open, and we did not want to put the public at risk.
"The horns were in the CRC for the last year. They would be powdered up and sold in the medicinal trade in the east, and would be worth about €500,000."
And he admitted that the horns were not insured, despite their value.
"Generally, the museum would insure items which are sent on loan to other institutions. Generally, state heritage is not covered by insurance because you'd be spending a fortune on insurance premiums. They were not insured.
"We would hope that the rhino heads are recovered . . . Unless you've got connections to the Far East trophy heads would normally fetch a couple of thousand euro."
Anyone with information has been asked to contact Swords garda station on 01 6664700.