Previous Heinous Crimes Units
From Save the Past
Although not directly pointed out by the game, there is evidence in The Silver Case of previous Heinous Crimes Units operating before the Heinous Crimes Unit of Ward 24 was founded (in 1990).
In case#3:parade, the documents found in the Yukimura Zaibatsu Warehouse mention a Heinous Crimes Unit that was based around the Mikumo 77 area in the '70s and possibly earlier. This Unit was doing investigation into "inheritable crime".
In case#4:kamuidrome, KamuiNet's list of crimes committed by Format Kamui also mentions a Heinous Crimes Unit in the profile for a case from 1977.
