BUCHAREST (Reuters) - Romanian experts believe that three out of seven paintings stolen last year from a Dutch museum, a haul that included works by Picasso and Monet, have been destroyed by fire, the team's head told Reuters on Monday.
Their findings appeared to back testimony by the mother of a Romanian suspected of leading the robbery that she had burnt the paintings to protect her son as police closed in.
"We gathered overwhelming evidence that three (of the seven) paintings were destroyed by fire," said Gheorghe Niculescu, head of the team from Romania's National Research Investigation Center in Physics and Chemistry, which has been examining ashes found in the police investigation.
However, he could not say which of the seven paintings had been destroyed and did not explain how he was certain that the remains originated from works stolen from Rotterdam's Kunsthal museum last October, rather than other paintings.
Also among the stolen artworks, estimated to be worth tens of millions of euros, are pieces by Matisse, Gauguin, Lucien Freud and Meyer de Haan, a 19th century Dutch artist.
In one of the most dramatic art thefts for years, the thieves broke into the Kunsthal building, somehow evading its sophisticated alarm system. None of the seven works has been found.
Romanian police said this year that they had detained members of a gang they suspected of carrying out the robbery. Soon after, Olga Dogaru, the mother of the alleged ringleader, told prosecutors she had burned the paintings to destroy evidence that could incriminate her son.
Prosecutors said they did not know if Dogaru's testimony was true or a trick to throw investigators off the scent and could not reach any conclusions until experts had completed tests on ashes recovered from an oven at Dogaru's home.
Until Niculescu spoke to Reuters on Monday, none of the experts involved in examining the ashes had given a firm view on whether any of the paintings had been destroyed.
Niculescu said he was now sufficiently confident that three had been destroyed that his department, a unit of the culture ministry, would be submitting a detailed report to prosecutors this week.
He said nails used to fasten the canvases to their wooden frames, recovered from the ashes in Dogaru's house, had been a crucial piece of evidence. "Their shape, the way in which they were manually manufactured and the metals they were made of, lead us to our conclusions," he said.
"We used X-ray fluorescence, X-Ray diffraction techniques, electronic and optical microscopy. I also got the best opinion of the national arts museum expert and there's no doubt here."
"Also Prussian Blue, a paint pigment discovered around 1715 and used on a large scale by painters from around 1750 ... which we found in very small traces of canvas, supports the case," Niculescu told Reuters.
The works stolen were Picasso's "Tête d'Arlequin", Matisse's "La Liseuse en Blanc et Jaune", Monet's "Waterloo Bridge, London" and "Charing Cross Bridge, London", Gauguin's "Femme devant une fenêtre ouverte", De Haan's "Autoportrait" and Freud's "Woman with Eyes Closed".
When they were stolen, specialists in recovering missing artworks said there was a good chance of recovering them. They said such pieces were so well known that it was almost impossible to sell them on the open market.
But the conclusion by Romanian experts that at least some of them had been burned dashed hopes that the stolen paintings could all be recovered intact.
Dogaru declared she originally buried the paintings in a cemetery near her home in the southeastern Romanian village of Caracliu. She told prosecutors that when police began searching for the paintings in the area, she dug them up and burned them in February in a stove in her home.
Romania's DIICOT government prosecuting office, which is investigating the case, was not immediately available for comment.
Police were put on the trail of the suspects by combing through security camera footage from the period leading up to the robbery, looking for visitors whose behavior suggested they might be making preparations for a robbery.
Security camera footage released at the time showed thieves entering through a back door and disappearing from the camera's field of view. Seconds later they reappeared carrying bulky objects and left the building by the same entrance.
editing by David Stamp