Gosick: Gray Wolf Tanteisha-hen

1931, New York. Victorique and Kazuya now live new lives as private detective and newspaper reporter. Victorique is asked to handle a case regarding a string of murders related to gangs, while Kazuya heads to a news coverage of a well-known psychiatrist famous for "curing the psychological traumas of patients by using the science of the heart." The mystery of the serial murder case lies in the fact that the scenes of the crime, the methods of killing used and the profiles of the criminals vastly differ from one another, while the psychiatrist utilizes the mysterious dream diagnosis for counseling. Before long, a link forms between the two cases, transforming into a dreadful conspiracy...

(Source: Kadokawa, translated)