Five paintings allegedly by Adolf Hitler failed to sell at an auction in Germany amid questions concerning their authenticity, as well as public furor.
It is feared the works could be fakes after prosecutors seized 63 other paintings attributed to Hitler from the Weilder auction house in Nurembrurg to investigate them.
The development comes after German police last month seized three paintings ostensibly painted by Nazi leader Adolf Hitler between 1910 and 1911, questioning the authenticity of the artworks.
The paintings received no bids, despite asking prices of between €19,000 (A$30,308) and €45,000 (A$71,783).
Antje Gabriels-Gorsolke, spokeswoman for the Nuremberg-Fuerth prosecution department, told Agence France-Presse that they had opened an investigation into certain individuals "on suspicion falsifying documents and attempted fraud".
Hundreds of Hitler artworks are known to exist, though most are held by the United States Army, which confiscated them after the allies defeated his regime at the end of World War II.
As a young man, Hitler unsuccessfully struggled to succeed as an artist in Vienna before World War I.
He was twice rejected from the Vienna Academy of Fine Arts, and his works are widely regarded among art experts as being poor quality.
A picture taken on February 8, 2019 shows the watercolour entitled "Ortschaft an Vorgebirgssee", a scene of a village near a mountain lake, signed "A. Hitler", which is on display at the Weidler auction house in the southern city of Nuremberg.
The sale also included items said to have been owned by the dictator, including a vase and a wicker chair with a swastika on its arm. It also failed to attract a bidder.
Under German law, the use of the Nazi symbol is illegal except for a few circumstances such as education.
The auction house got around the law by pixelating the symbols within their catalogue.
Nuremberg's mayor, Ulrich Maly, had earlier condemned the sale as being "in bad taste".