Officer Sugimoto

Junsa is a minor character who was featured in Chapter 6. He is a rookie police officer who served under Yamagawa and Minouchi, also being the former's killer.

Background
Sugimoto had failed the police entrance exams three times. At this point he was already on the brink of giving up, but then a certain politician had approached him and aided him in getting into the police force. In exchange, Sugimoto would have to follow his orders.

It is also of note that Sugimoto had been in a relationship with Yamagawa.

Plot
Sugimoto had been contacted by the politician which he had been working for to get rid of the evidence Yamagiwa had against him. Sugimoto had called Yamagawa out early in the morning to talk about it.

Yamagawa had refused to hand over the evidence and so Sugimoto had threatened her with a gun. When Yamagawa had known Sugimoto could not shoot her, he changed his threat to shooting himself in the head.

Yamagawa had panicked at this and tried to stop Sugimoto. In the process, he had accidentally killed Yamagawa by shooting her in the chest.

The diet member had then told Sugimoto how to cover up his crime.