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Artist's commentary
輝ける太陽の殺人
以前頒布した東方ミステリー漫画です。
I'm afraid not.
The phones used at the lab are a primitive model they developed themselves that can't identify the caller.
Lecture room
Courtyard
Storeroom
Storeroom
I see.
So after attacking Reisen, the culprit left the boiler room and made the call from the night duty room.
Boiler room
Outside the lab
Window
Window
Ringo
Reisen
Night duty room
It's on the other side of the boiler room exit. It should've been empty at the time, though.
Also, there's an internal line in the night duty room.
Night duty room?
Only about 15 seconds.
5 sec
Window
They sound weirdly calm to have just killed someone, but I suppose they had locked the door behind them and were at no risk of being pursued.
10 sec
*Ringo's internal clock
So, any questions?
Hey, wait. Can't they know from the call's data whose phone it was made from?
How much time passed between you leaving Reisen and hearing her scream?
About 10 seconds from when I heard the boiler room door open, though.
Judging from the time, Reisen might've been stabbed after exchanging only a word or two with the assailant.