Guest was summoned to Rei's private compartment.

I didn't expect you to be here. Well then, I'll explain the overview of this case immediately.

Guest took out a notebook.

The male victim discovered earlier was dead in his private compartment. There were no external injuries, and the door was locked from the inside. At this point, it's a locked-room murder. There are no signs of a struggle at the crime scene. The victim's smartphone, clothes, and an empty whiskey bottle were on the desk. Since the victim seems to have liked whiskey, it's not unusual for an empty bottle to be there. They are sold on the train. The estimated time of death is roughly around 21:18. Exactly when this train entered the long tunnel. The victim is a man in his 50s, a former business executive named Kenji Sudo. In the past, he covered up scandals and fired whistleblowers. Since there are no signs of poison ingestion, there is a high possibility of homicide.

There are five people on this train, excluding us.

She sat down across from Guest.

First, Makoto Fujido. She's the conductor of this train. Before and after the time of the crime, she was talking to a passenger, Mio Kanzaki, on the deck. After that, she was managing and recording train operations. Since it's recorded in the logs, she's as clean as can be at this point.

Next, Mio Kanzaki. A high school girl traveling alone. Since she was talking to Ms. Fujido around the time of the crime, she is also as clean as can be. The content of their conversation was perfectly normal—advice about life, the train, her travels, and so on.

Next, Koichi Kiryu. An office worker and the victim's former subordinate. Apparently, their relationship wasn't very good. He claims he was looking at his smartphone in his room around the time of the crime, but there are no witnesses. Furthermore, a bottle that appears to have contained poison was found in his bag. He strongly denies it... but he is a primary suspect.

Next, Rina Aizawa. A freelance journalist who seems to have been investigating the victim's past. She was confirmed to be near the onboard sales cart around the time of the crime. She even had a brief conversation with the vendor. However... for the few minutes after entering the tunnel, she has no clear alibi.