Blue Shadows.

This time the detectives deal with the case of a murdered professor. One day a cleaning woman finds him shot to death in his own study. The detectives will thus investigate whether the murder is connected with the victim's persistent effort for the removal of the University's quaestor because of the latter's strange machinations during the reconstruction of the University building. And they'll also want to know why the murderer took the great risk involved in killing the victim on the university soil. The search for the answer to the question who could wish the death of the peculiar but honest professor will take them farther than they have expected.