What are the motifs in Whose Body?: A Lord Peter Wimsey Novel by Dorothy L. Sayers?

Attention to clues is a recurring idea in the story. Peter and Parker are involved in a series of questions that seem to have a series of answers but that really are a series of connected events. The two crimes are the disappearance of financier Reuben Levy and the appearance of a naked body in the bathtub of a prominent architect. The series of questions involve the presence of an expensive pair of glasses, the importance of a Peruvian oil stock, the level of involvement of an American businessman and an elderly attorney.