Perfect Crime Arc

Perfect Crime Arc (完全犯罪編,) is the fifth story arc of Bungo Stray Dogs. It introduces a new member of the Rats in the House of the Dead in the aftermath of the Cannibalism incident.

Synopsis
After the cannibalistic mutual destruction, a Rats in the House of the Dead member who is capable of suppressing evidence appears - responsible for framing Doppo Kunikida for murder during their pursuit of a virus ability user. A battle between Ranpo Edogawa and the member takes place as the former tries to free Kunikida from jail.

Kunikida's Arrest
Kunikida is arrested for murder of a child during the Armed Detective Agency's pursuit of a virus ability user who who is responsible of infecting Yukichi Fukuzawa and Ōgai Mori. Ranpo vows to get him out of jail and clear his name.

Pursuit of the Evidence Suppressor
Ranpo's bumps into Poe and asks for his help to catch the evidence suppressor. During their wait, Poe shares that the author of the mystery tale he's tackling was killed, the same method that was in the novel. Intrigued, Ranpo decided to name the culprit behind the author's murder. The manuscript bid by Poe in an auction turns out to be the same manuscript the killer stole from the author and decided to sell it. They found a red envelope containing the manuscript which was supposed to be carried by a stranger. Upon getting it, a man falls down from above and turns out to be the evidence suppressor's face.

Minoura and his subordinate shortly arrives to the scene. Ranpo deduces that the evidence suppressor faked his own death using the guy. The real evidence suppressor named Mushitarō Oguri is spying on the scene, he proceeds to use his ability to erase the evidences. Ranpo fails to know the culprit behind the death of the guy, stating that he doesn't know any of it.

Mushitarō's Arrest
Shortly after, Mushitarō was approached by Ranpo and asks for his help to get to a taxi stand to get back to the agency office. During their conversation inside a car, Ranpo shares his thoughts about the fake suppressor's death case and explains how the culprit executed his plan - the same person who killed the author and stole the manuscript. Ranpo then points to Mushitarō and reveals him being the culprit to both crimes.

However, the police weren't able to immediately arrest Mushitarō due to the car having diplomatic plates - resulting to it being immune to investigation. Failed to catch Mushitarō, Ranpo still vows to defeat him. Mushitarō sees a phone full of text language, upon opening it, Mushitarō is transported to the murder scene where Mushitarō killed Yokomizo, the author. Ranpo reveals the truth behind the Kindaichi murder to be a suicide particularly the author's wish to put the novel's scheme into reality. Ranpo then makes Mushitarō choose - to either surrender or he will reveal this theory to the public. Fulfilling his friend's wish to not reveal the scheme, Mushitarō surrenders himself to the police.

Impact

 * A Rats in the House of the Dead member was revealed.
 * Mushitarō surrenders to the police.
 * Doppo Kunikida was freed from jail.

Trivia

 * The arc is in reference to how the Mushitarō's "" was written in real-life. "The Perfect Crime" was originally 's story which he had to stop writing due to him catching an illness, Mushitarō then took over the writing of the story until it was finished, becoming his debut novel. This is symbollically referred to in the arc with Mushitarō killing Yokomizo leaving the story he was writing unfinished.