Bavarian sunset

Sam Grant had to trace the vendor of a painting that had come up for sale at a London auction room. By a German Jewish artist who had perished in a Nazi concentration camp, the painting had been stolen from a schloss in Lower Saxony in World War Two. Then it had appearently vanished, until surfacing fifty years later. So who had possessed it in those years? Grant had to find the answer fro Gerda Hoffman, an attractive blonde. But the case turned out to have a fatal aspect.