Funny how that happens

Several months ago I read Wikipedia entries about the Warburg banking family. Paul Warburg was the architect of the Federal Reserve System, while his brother Max was an influential German banker. What I recall is that mention was made that Max was also head of the German secret services during World War I, while his brother Paul was on the Federal Reserve Board. This fact seemed more strange to me than that the King, Kaiser, and Czar were all cousins.

But now I see no mention of Max's service as top spy. The only sites mentioning it are so-called conspiracy sites, which are often impugned for inaccuracy, exaggertion, or wild speculation.

So was Max the man who gave Lenin safe passage to Russia? If this is true, why pretend that it's not? And if it isn't true, is not the conspiracy community just discrediting itself?

Or does it remain a "secret" who was in charge?