A painting believed to be by Dutch master Vincent van Gogh was found by Spanish tax inspectors inside a safety deposit box. The rediscovered oil is thought to be van Gogh's "Cypress, Sky and Field"  of 1889 that was last seen 40 years ago at Kunsthistorisches Insitut in Vienna.

Spanish newspaper El Mundo reported that a source said an investigation is underway to determine if the painting was stolen and how it came to be in the bank vault. The owner of the safety deposit box said he was storing the painting for a millionaire friend who has not been identified.

According to El Mundo, the van Gogh seizure was part of a larger operation to confiscate the contents of 542 safety boxes from tax offenders who owed about 319 million euros ($438.83 million).

The authenticity of the van Gogh painting, measuring 35 by 32 centimeters (13.7 by 12.5 inches), will be assessed by Spain's Culture Ministry.

It bears three seals on the reverse. One, dated April 8, 1944, is for the Rijksmuseum in the Netherlands. The seal and red wax match those used by the Nazis during the occupation of the Netherlands, reports Gizmodo.

Another places the painting at the Museum der Schöne Künste in Berlin, but bears no date. A seal dated April 10, 1975 takes the painting to the Kunsthistorisches Institut der Universität Wien, the art history institute at the University of Vienna.