The culprit is Itaru Kaburagi. The victim, whose real name was Ari Sukiyama, was a marriage swindler who tricked Itaru's good-natured older brother into supporting her, leaving him with a huge debt that drove him to suicide.
The culprit is Reisuke Inaba. He killed Ninka because she threatened to reveal their affair to the media unless he divorced his wife. He also killed Kabumoto because the latter blackmailed him even though Kabumoto was the one who introduced the married Ninka to him. His resolve to murder him was set when the victim told Reisuke that the reason he introduced Ninka to him was that he could write better scripts if Reisuke cheated for once.
After the case, Iori brings Ran and Kazuha to the scene. He has a conversation with Kuroda, who calls him Sakakibara, a codename Iori had when undercover as a Public Security Bureau officer in the past. Iori also mentions he meta blond-haired man at Café Poirot and thinks that he is restrained by his past bonds.
A black vehicle then passes near the scene with a mysterious old man on defibrillator as its passager. The old man then says to himself that the police are nothing but a bunch of fools. From his aura, it is suspected he might be Renya Karasuma, while his driver's looks make him resemble Billy, Fusae Campbell's driver.