Hallway (detention center)

A hallway in the detention center leads to various rooms such as the holding cells, a monitoring room, the warden's office and the prison.

Contents
The doorway leading to the prison and the doorway leading elsewhere in the detention center have security gates. This means that the passage of people through this area is heavily secured, though packages undergo a simpler check and items could be smuggled through this method. Throughout the hallway are lockers for the guards. The hallway also contains a trophy display case. Above it are four framed profile photos of four people. There is a sign near the door to the monitoring room.

Prison murder

 * Main article: The Imprisoned Turnabout

In the 2010s, Marī Miwa was appointed warden of the prison. Her dubious past began to catch up to her when assassin Ryōken Hōinbō was caught and sent to the prison. Hōinbō had information that could implicate Miwa in a past incident, allowing him to coerce the warden into giving him special privileges. Hōinbō became known as "the Supplier" due to his ability to get items delivered to his fellow inmates through this coercion. Miwa would frequently interrogate the assassin to try to get him to reveal the information that he had, but he never budged.

Shūji Orinaka, an inmate at the prison, took advantage of the Supplier's services to attempt an escape. Using stolen kitchen utensils, he dug a tunnel to the holding cell. On March 25, 2019, Manosuke Naitō was arrested and detained in the holding cell. A day later, Orinaka attacked Naitō and an escorting guard to steal the keys to the holding cell. The other guards blamed Naitō for the attack. Later, at Orinaka's request, a guard uniform was stolen from one of the lockers.

The next day, Miles Edgeworth, the prosecutor in charge of Naitō's impending trial, visited the detention center to talk to him. However, a guard told him that Naitō had just been found dead. Edgeworth hurried to the detention center hallway, but was surprised when the guard led him further in, reaching the prison. Judge Hakari Mikagami and prosecutor Yumihiko Ichiyanagi visited later on, sent by the Prosecutorial Investigation Committee to replace Edgeworth as the lead investigator.

The investigation conducted by Mikagami and Ichiyanagi continued to the following day, and failed to find a murder weapon. However, they arrested Sōta Sarushiro as a suspect. Tateyuki Shigaraki, Naitō's defense attorney, took Sarushiro's case. As he was heading through the detention center hallway, he found Edgeworth with Kay Faraday and Dick Gumshoe, who were trying to find a way to continue investigating. After some convincing by Faraday and Gumshoe, Shigaraki agreed to take Edgeworth on as an assistant.

Shigaraki returned to the detention center while Edgeworth was interrogating Hōinbō. He learned from the guards of the earlier incident with Naitō. When Edgeworth was finished with Hōinbō, he returned to the detention center and found Miwa talking to one of the guards about her interrogations of the assassin. Edgeworth then investigated the holding cell, during which time Interpol agent Shi-Long Lang visited the detention center. Lang was investigating the incident from Miwa's past, but would not discuss this with Edgeworth when the two briefly crossed paths.

Mikagami and Ichiyanagi left the prison to see Edgeworth talking to the guards. Despite Mikagami's attempt to get Edgeworth to leave, Ichiyanagi decided to challenge his senior in an argument on the case. His arguments turned out to be very flimsy, with Mikagami picking up the slack and explaining the many holes in his logic. However, the argument simply raised more questions as Edgeworth failed to demonstrate his working theory that Naitō had been killed inside his holding cell.

Later, Orinaka made his escape, disguising himself as a guard using the stolen uniform. However, he could not leave due to a shock bracelet that he was forced to wear as a prisoner, and was eventually caught after Edgeworth had discovered his tunnel. The next day, Edgeworth continued his investigation and figured out the secret behind the Supplier. He concluded that Miwa was the killer, and found the murder weapon inside Ally, her pet alligator.