Paintings by Picasso, Monet, Matisse and others may be gone forever after possibly being burned in a stove in Romania. The paintings were stolen from a Dutch museum last fall.

Ernest Oberlander-Tarnoveanu, director of Romania’s National History Museum told the Associated Press that ash discovered in woman’s stove in Romania may be the remains of the artworks. The woman’s son is among three men charged in the October 16 heist at a Rotterdam museum.

Oberlander-Tarnoveanu told the AP that he could not say for certain that the ash was the paintings, since he’s not in the position to make that confirmation. He said justice officials will do that after the ash is analyzed.

The paintings were on display at the Kunsthal Museum in Rotterdam for the museum’s 20th anniversary celebration. All the pieces were from the Triton Foundation and had never been on display before. The thieves made off with works by Claude Monet, Pablo Picasso, Henri Matisse, Lucian Freud, Paul Gauguin, and Meyer de Haan and it was considered the largest art heist in the Netherlands in decades.

According to The Guardian, the thieves needed just two minutes to complete the heist and police arrived five minutes after they left.

Three men from Romania were arrested in January and none of the pieces were recovered at the time.