A piece of wood hewn from an Alpine fir is among evidence that has led a renowned collector and authority on rare instruments to be labelled a con man, suspected of the world's biggest violin scam.
In April last year, suspicious bank officials in the German port city of Bremen called in a forestry expert to examine two legendary Stradivarius violins they had been given as collateral for a €5.9 million ($9.8 million) loan.
The instruments, said to have been created by the famed 17th- and early 18th-century Italian violin-maker, were supposedly 294 and 325 years old respectively. They had been given a combined value of €5.2 million - easily enough to cover the bank's loan.
But when Hamburg tree expert Micha Beuting subjected the instruments' pine board to a scientific "age test", he discovered they could not possibly be genuine Strads.
The growth rings in the wood showed that the trees used to build the instruments were cut down decades after Antonio Stradivari died in 1737.
The pair of violins were worth a mere €2000 each.
Violin expert Roger Hargrave, called into Bremen's Sparkasse bank to examine the instruments, said: "The bankers were completely shocked. There was no oxygen left in the room. They were extremely embarrassed to have fallen for such a huge trick."
The man accused of perpetrating violin fraud on an epic scale over decades is German businessman and entrepreneur Dietmar Machold, a wealthy and internationally known collector and purveyor of rare violins who was nicknamed "Mr Stradivarius" around the world.
Machold once had offices in Chicago, New York, Tokyo, Seoul, Zurich and Vienna. He drove a yellow Rolls-Royce, lived in a sumptuous 700-year-old castle near Vienna and played the role of celebrity businessman and society host.
Austria awarded the Bremen-born businessman the title of honorary professor.
Machold, 62, is in an Austrian prison awaiting trial on charges of embezzlement, bankruptcy, and the offence of grand commercial fraud. He is suspected of swindling creditors out of €100 million with the help of faked and real Stradivarius violins.
Vienna prosecutors have received 46 complaints relating to criminal charges against Machold, from banks and individuals in Australia, Holland, Germany, Belgium and the United States. The complainants include the owners of more than 200 string instruments which have passed through Machold's hands at some stage.
Prosecutors are piecing together evidence that alleges Machold's business activities degenerated into a giant game of bluff. Banks and collectors of luxury items such as rare violins were systematically conned out of millions in cash or priceless instruments.
There are an estimated 600 Stradivarius violins, 60 cellos and 12 violas still in existence. Many had been handled by Machold.
Machold's career as a collector and dealer in priceless violins was initially hugely successful, but in 2010 his company collapsed.
Using faked Strads and occasionally genuine instruments, he used his reputation to persuade creditors to hand him huge amounts of collateral.
But the cash was been used increasingly to pay off a growing mountain of debts. In the end, Machold was trapped in a spiral of deception, prosecutors claim.