There is an increasing amount of evidence that seven paintings stolen from Rotterdam’s Kunsthal museum last year may have been burned, after traces of paint and nails were found in ash in the house of one of the defendants, Nos television reports.

Remains of paint and old nails were identified in ash in a stove by Romanian investigators. They are now being analysed in a laboratory, Nos said.

Earlier there were reports that the mother of one of the suspects had burned the paintings because she was frightened her son would get into trouble.

Picasso

According to Dutch officials, there is still no certainty about what happened to the haul, which included works by Monet, Picasso and Matisse. They were briefed by the Romanian investigation team on Tuesday.

The total value of the paintings, which were part of the Triton Collection, is put at around €18m.

Six people will go on trial in Romania later this year in connection with the theft.

Birds

More details about the robbery are also emerging. Website nu.nl says the Romanian investigation shows the thieves first considered breaking into the nearby natural history museum but decided stuffed birds would not raise much money.

After reading posters about a new exhibition at the nearby Kunsthal, they then changed target and cased the museum several times before the theft on the night of October 15.