There are several conditions to the payment of the reward.
Since the publication of the book many people have tried to assist Karl to solve the puzzle. This lead to some promising and exiting moments. However, per 12.12.2014 no definitive results were achieved. For this reason Karl has set a deadline for the reward on June, 12th 2015.
After the closing date of June, 12th 2015 Karl will evaluate all the (new) relevant information, review it with its sources and experts and consider an update or sequel for the book. In the late Summer of 2015 Karl will travel to the Alps for a final attempt to find the hiding place of the gold and diamonds. Also it may be interesting to read about the attempts made by several other people but which thus far have proven unsuccessful. Less serious are the conspiracy theories that have started to surround the book. Most of them are directed against Karl personally and claim he is in fact a Werewolf-agent. Obviously these people have not read the book where Karl condemns Nazi atrocities and fascism, writing about the Holocaust: "As far as I was concerned, there had most certainly been a resolute persecution of Jews and other minorities. But the number of victims, in my view, was irrelevant. Even if only one person had been persecuted per day because of religion, race, physical defects or social status, it was still one too many."
Other conspiracy theories claim that Karl is an agent of the Vatican, of the Russian KGB, the American CIA, British MI5, MI6, and many other agencies or secret societies. Although these theories are merely attempts to discredit Karl they provide a rather humorous addition to any update or sequel.