Bungo Stray Dogs: Gaiden

Chapter 1: The old church within the mountains.

"Then – How?"

"Ahh... How, you say. It's come to that after all."

Ayatsuji muttered under his breath with a sigh. Everyone in the room grew anxious from the strange silence, exchanging glances with one another.

... Had something bad been said?

"Oh well. Don't worry. I've already known all of you don't have brains that can think. For some reason, the people involved in a case always think it's the detective's responsibility to put together the case piece by piece like some gentle mother. It's similar to kindly teaching how to put on a diaper, I think. It's simply charming."

Everyone there gave a blank stare. They weren't able to comprehend what the detective had said about them, how they were supposed to feel hurt. They would surely grow angry the next morning.

The detective sucked on the mouth piece of his pipe he held between two fingers, slowly exhaling a thin cloud of smoke. Then, he spoke. "Do you know of Ockham's Razor?"

"Razor...?"

They all looked at each other with bewildered expressions.

"It's a principal of philosophy. 'Suppose there exists several theories for an occurrence. In this case, the simpler one is usually better' — With these guidelines, the simpler theory is more likely to be the truth."

Ayatsuji gazed at the others while explaining before continuing.

"Only one person among the children who ate the same meal was killed. In that case, the explanation is simple. Poisoning everyone else the same way, the poison used was aimed to kill just one person. It's an incredibly simple solution. That kind of poison exists. It is also easy to find in nature."

"Eh..."

The audience was stunned. Ignoring the stir, Ayatsuji continued while holding the pipe between his lips.

"The culprit applied an adhesive of the poison to the tableware the day before. All of the tableware, equally. And... using the timing when everybody began eating their breakfast, the culprit deliberately made the victim leave his seat."

The teachers thought back on it. It was true, 20 minutes before the incident, the boy received a scolding for twenty minutes as a teacher's wallet, which had been stolen, was found in his bag. However, it was done in the corner of the room, and due to the fact that everyone had seen the scolded child, it was seen as unrelated to the incident.

"Then... Someone poisoned him at that time?"

"It seems you do not have even a sliver of memory. I said the poison was already applied, didn't I?" Ayatsuji said with cold eyes. "The poison was applied to the egg beating bowl. And – 1 gram of that poison can easily kill a million people, it's one of natures most strongest deadly poisons. Natural producers of this poison can be present in the soil or at the bottom of a lake and it grows tremendously under certain nutrient conditions."

"I see!" The previously silent administrator of the facility suddenly shouted. "Botulinum poison...!"

Ayatsuji nodded as he continued. "Botulinum is an anaerobic bacterium of the Clostridium genus which produces an extremely potent Botulinum toxin. Terrorists have used this dangerous toxin as a biological weapon. The raw eggs, when the yolk and egg whites were mixed together, caused it to grow tremendously. By itself, it's nearly harmless to the body, however, once grown in food and ingested, it will result in death within 8 to 32 hours."

He walked quietly as he proceeded, speaking the truth with ease. Despite the old age of the church, his shoes never caused the floorboards to creak.

"Eyeing the timing after everybody had mixed their eggs, the culprit controlled the situation by interrupting only the victim's meal, and bought the time needed for the bacteria to grow. Specifically, they were called to a corner of the room, and disciplined for a long time. By doing so, they were able to create the unusual circumstance where only the victim was poisoned. Because all of the other classmates were eating the same thing, the idea he was the only one who had his food altered with a deadly poison would be seen as inconceivable."