Too Many Women by Rex Stout

An employee of a very large corporation dies in a hit-and-run accident. Rumors abound that it was murder, disrupting morale. Nero and Archie are hired to either scotch the rumors or find the truth re: the mysterious death. These circumstances put Archie smack dab in the middle of hundreds of young working women -- many of them suspects, most of them of interest to Archie on other levels.