Apeman's Secret, The (The Hardy Boys #62) by Franklin W. Dixon - Vintage Paperback

The Hardy Boys investigate the disappearance of an eighteen-year-old girl suspected of joining a sinister religious cult.

A few days later the boys get an offbeat assignment from a comic book publisher: The real life double of his character, Apeman, is turning up everywhere and causing considerable damage! Frank and Joe tackle both cases and uncover an intricate scheme by a clever gang of crooks!