San Francisco - California Governor Arnold Schwarzenegger on Friday returned artwork stolen by the Nazis to the heirs of Holocaust victims. Schwarzenegger presented three 16th century oil paintings to the grandchildren of Jakob and Rosa Oppenheimer, who fled Nazi Germany in 1935.

The contents of their art business was sold by Nazis and ultimately ended up in the collection of newspaper mogul William Randolph Hearst, who displayed them in his castle in California. The state said it believes Hearst was unaware of the paintings' origins because they were not bought directly from the Nazi sale, but were instead purchased through a third party gallery.

The state acquired the art along with the Hearst Castle in 1972. An inquiry by the Oppenheimer heirs prompted a two-year investigation that showed they had a claim to the paintings.

One of the paintings is to remain at the Hearst Castle at the heirs' request along with reproductions of the other works. They will be used to tell the story of how assets were seized by the Nazis.

"More than 1 million people from all around the world visit Hearst Castle every year," Ruth Coleman, director of California State Parks, said. "We are proud to honour the memory of Jakob and Rosa Oppenheimer and share this story that touches countless families affected by the Holocaust."

The oil paintings by Venetian masters were done between 1500 and 1590 and include a woman's portrait by Jacopo Tintoretto (1518-1594), an image of a man believed to be done by Giovanni Cariani (1485-1547) and a Venus and Cupid by Paris Bordone (1500-1571).

Jakob Oppenheimer died in France in 1941 and his wife, Rosa, died in the Auschwitz concentration camp in 1943. (dpa)