Bomb Threat Case

The Bomb Threat Case (爆破予告事件,) is another case sent by the same client responsible for requesting to investigate an abandoned building.

Prologue
The agency have received another request to defuse a bomb. If the agency don't find and defuse it by sundown the next day, over one hundred people will die.

Case

 * This summary follows the light novel.

The agency members have gathered in the agency's conference room. Kunikida addresses them and hands out the necessary documents regarding the case. He states to them that the agency is currently being threatened and shares the email they received from the offender.

The agency has sent workers currently searching for possible locations where the bomb may be located. Kunikida have also been asking distributors if they know anyone purchasing a large number of surveillance equipment however they have received any leads that might help them. Kunikida have also been in contact with an affiliate who's making list of candidates who specializes in explosives and may have a grudge against the agency.

During their investigation, Fukuzawa have been in contact with Ranpo earlier however he will not be able to go back soon as he is investigating a case in.

Fukuzawa proceeds to question Kunikida if it would be possible to have an interview with the taxi driver- the one responsible for the kidnappings of Yokohama visitors. Fukuzawa proceeds to take the responsibility to speak with the military police's intelligence department and orders Kunikida to get in contact with whoever he can on the aircraft where the taxi driver is currently on board and have him answer their questions. Fukuzawa then gives his final orders to the agency members: find the aggressor and disarm the bomb.

Kunikida contacts Rokuzō Taguchi in hopes of having known the location of the client from the first email they sent. However, Rokuzō tells that the culprit is using multiple hubs to hide their tracks. Kunikida then asks Rokuzō if he could find the source of the second email. Rokuzō proposes that he can send a virus to the hub and use it to trace the source though him breaking the law. Kunikida gives him the permission to do so.

During the investigation, Kunikida finds Dazai in a café chatting up with Nobuko Sasaki. Kunikida updates him regarding the case in which the taxi driver admitted to kidnapping the victims and gasing them but didn't know about the surveillance equipment. This leads to their conclusions that there must be as least two people behind the incident - the taxi driver who kidnap the victims and the Azure Apostle who recorded everything.

Kunikida and Dazai go to the United States Embassy on a mission, with Kunikida dressed in a high-end navy business suit and tie while Dazai is wearing a raggedy, patched-up undershirt. Dazai begins to cause a disturbance at the embassy demanding on seeking refuge. Before the guards rush towards Dazai, Kunikida defends Dazai and recites the article 31, paragraph 2 stopping the guards from their tracks.

It is revealed that Sasaki have tried to help Dazai and Kunikida on getting information about the bomber. She reveals that she contacted a colleague of hers regarding bombing cases in Japan that has claimed over a hundred lives, but unfortunately there has not been an incident like that. She further shares to them that there are few dozen terrorist attacks in other countries.

Kunikida shares to Dazai that the and the military police-affiliated organizations have looked into domestic bomb-making experts and they didn't find any suspects who possesses the refined technology needed to make high-grade explosives that could kill over one hundred poeple. Eventually, Dazai shares information that foreign intelligence agencies have records on past bombing suspects hence how Dazai and Kunikida went on an undercover mission at the embassy to be able to talk to a high government official.

After causing a ruckus at the embassy, Kunikida is approached by the receptionist who is constantly bugged by Dazai. Kunikida reveals that he is Dazai's chief editor and nothing will make him give up on his demands unless a civil security with authority comes and talks to him directly. They were then taken to a diplomatic reception room where a bald Caucasian diplomat appears to have been waiting for them.

Soon after meeting the diplomat, Kunikida pulls out a black notebook and tells that they are with the Tokyo Metropolitan Police Department's Public Security Bureau, revealing that they needed to take an unconventional route in establishing contact with them.

Kunikida proceeds to tell that that they need data on bomb engineering specialists within Japan and if the attaché can introduce them to someone who does. The attaché speaks with a secretary and reveals that the Public Security Bureau's director will be coming soon. Hearing this, Kunikida panics and tries to improvise a reasoning as to why the director can't be present. Dazai steps up and tells the attaché that there is a mole in the bureau who's feeding information to the bomber and they are currently doing undercover as not to leak intel.

The attaché soon brings them to a private office in the embassy's basement. A US intelligence operative arrives which is the same man who had been watching a ball game at the embassy hallway earlier. He reveals that they've had their eye on Kunikida and Dazai right when they walked into the embassy.

Kunikida proceeds to ask the operative if they know a person who might have set bomb in the city, the one also responsible for similar bombing cases overseas. The operative reveals the name to be Zadkiel Alamta and the bureau have been keeping tabs on him since he entered Japan a year ago.

After learning the bomber's name and background, they head back to the agency to organize some information from the documents. Kunikida gets help from Ranpo who just had returned from his case in Kyushu. Ranpo soon pinpoints the location of the bomb which is at a fishing gear shop using his ability.

Kunikida and Dazai soon head to the fishing gear shop and realizes that Alamta's real target are oil storage facilities which are near the shop. The two soon arrives at the shop and sees few cars parked near it. Kunikida finds a commercial vehicle. Kunikida manifests a wire jammer and gives it to Dazai for him to place it by the vehicle while Kunikida searches the vicinity.

Kunikida scouts the area and finds two recorrding devices hidden in the grass, confirming that the bomb is near the shop. Soon after, he hears people gathering on the other side of the road. Kunikida approaches the crowd and sees Alamta's body and finds "OO" on his body. Dazai approaches Kunikida and tells that he have place the jammer and also sees Alamta's body. Dazai tells Kunikida that the military bomb squad will be arriving and let them handle the technical stuff. The two soon plow through the crowd and leaves the scene.

Resolution
The case was left unsolved.

Novel and Anime Differences

 * In the light novel, Kunikida and Dazai perform an espionage mission at an American embassy in attempting to locate the bomb's location, where they learn about a bomb purveyor named Zadkiel Alamta and initially suspect him of being the Azure Messenger. In the anime version, both the espionage mission and Alamta's character are omitted.
 * Ranpo personally returns to Yokohama after his case in Kyūshū in the light novel, while in the anime version, he remains in Kyūshū and communicates with the Agency via phone call.
 * In the light novel, Dazai discovers that Ranpo's Super Deduction is not an ability after touching his hair to see whether No Longer Human could nullify Ranpo's ability, which does not. Dazai then concludes that Ranpo merely utilizes his regular deduction; this is also the first time that Kunikida learns about Ranpo's fake ability. This does not occur in the anime, though Dazai touching Ranpo's hair to try to "nullify" Ranpo's ability is shown in another episode.