In 1979, Kusabi, then a Regional Investigation Unit Special Agent, was involved in the event known as [[The Silver Case (event)|The Silver Case]], in which [[Ginji Nakane]], chairman of the [[TRO]]/[[CCO]] Confederation, was assassinated by [[Format Kamui]] in front of the TTV Station. Publicly, Kusabi arrested Kamui; however, as Kamui was actually killed, it is believed that Kusabi killed Kamui. Yet, Kusabi's personal version of the events maintain that Kusabi merely stood there and watched as Kamui was killed by members of the Confederation. Regardless of the truth, Kusabi was promoted to the Security Department where he remained until 1990, when he became one of the founding members of the Heinous Crimes Unit.

In 1979, Kusabi, then a Regional Investigation Unit Special Agent, was involved in the event known as [[The Silver Case (event)|The Silver Case]], in which [[Ginji Nakane]], chairman of the [[TRO]]/[[CCO]] Confederation, was assassinated by [[Format Kamui]] in front of the TTV Station. Publicly, Kusabi arrested Kamui; however, as Kamui was actually killed, it is believed that Kusabi killed Kamui. Yet, Kusabi's personal version of the events maintain that Kusabi merely stood there and watched as Kamui was killed by members of the Confederation. Regardless of the truth, Kusabi was promoted to the Security Department where he remained until 1990, when he became one of the founding members of the Heinous Crimes Unit.