She later retracted her statement, but Romanian art experts say they have discovered traces of three or four paintings in ashes taken from a wood-burning stove in her home.
Ernest Oberlaender-Tarnoveanu, head of Romania's National History Museum which analysed the ashes, said he could not be sure the paintings were those swiped from Rotterdam's Kunsthal museum last October.
"The number and the type of nails we found (in the ashes) indicate that we have at least three paintings there. There are also tacks that could belong to a fourth one," he told a press conference.
"We found remains of burned oil paintings, but whether they are the ones that were stolen is a separate question, to be determined by prosecutors and judges."
Olga Dogaru, her son Radu and four other Romanians go on trial on Tuesday in Bucharest over the audacious heist, which has been called the "theft of the century".
It took the thieves just a pair of pliers and less than three minutes and to break into the museum and snatch the masterpieces, according to the indictment.
Four of the stolen canvases were oil paintings, while the other three -- including Monet's "Waterloo Bridge" and Picasso's "Tête d'Arlequin" -- would be impossible to identify if burned as they were either pastel or coloured ink on paper, Oberlaender-Tarnoveanu said.
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