Finding Books

"That's right. You might not know this over at Beika Police Station, but Tokyo's recent arson cases were actually made up of multiple serial incidents. The most dangerous and troublesome of them all is the one involving the culprit codenamed 'Red Horse.' We still don't have any leads on that one, and the damage it has caused has been enormous!" Yumichika sighed, looking deeply troubled by the matter.

"Inspector Yumichika, do you have any leads on this arson case?" Amaki asked.

"This arson case is also a series of incidents, but unlike Red Horse, these cases have no obvious pattern and seem much more random. Still, they share two things in common."

"First, no one was inside the houses when the fires broke out. The culprit probably wasn't setting fires to kill anyone."

"Second, darts with burn marks on their tail fins were found at every fire scene. Traces of fire oil were detected on them afterward, and every point of ignition was near a window."

As soon as Inspector Yumichika finished speaking, Zilian immediately understood. "So the culprit threw burning darts into the rooms to start the fires?"

Inspector Yumichika nodded, confirming Zilian's words. "That's right. No traces of activity other than the homeowners' were found at the scenes either. Though this person commits the crimes in the early morning and targets residential areas, the fire department receives a call soon after each fire begins, so none of the fires have grown very large."

That struck Amaki as strange. "Could this really be prank arson?"

But if it was a prank, the scope of the crimes should not have been so broad—after all, the people who did this sort of thing were usually just little brats!

Yet Inspector Yumichika had just said that the crimes had no pattern, including