The Fu Manchu rights, to both films and books, are quite tangled. I looked into clearing the rights to the serial when I got hold of a nearly complete 35mm print many years ago. My partner and I paid a professional copyright researcher, who found conflicting data. So conflicting, in fact, that we abandoned the whole project and later disposed of the print. Republic renewed its copyright on the serial even though they had no right to release it commercially in any format. I'm more than a little sure VCI released the serial in the belief that nobody would come after them, precisely because there's such confusion about the rights.