If Rumi is the daughter/sister
of Haneda Kouji, that'd make sense she keeping her father/ brother's dying message shougi piece as keepsake/ memento
BTW Mary must be little sister of Elena(would make sense of little sister from outer domain, Aoyama's revelation about one of pair of sisters), both are of British descent, that'd makes sense why she looks like Haibara. Also Amuro might've been adopted by Elena.
Ano Kata is Aoyama Gosho himself, which is why musical notes sounds like Tottori area code, Yamamura is his son.
Vermouth might be Ano kata's daughter, hence why she was allowed to exclusively consume anti-aging drug to retain her youth.
reason why Boss likes Nanatsu no Ko is cause of there are Japanese theories that the crow cries singing in the song because it's cute babies (have died, which is indirectly stated by the crow crying), he most have lost important people too, also it might be possible that boss exactly wanted drug to shrink one into 7 year old, has anyone wondered why Conan has shrunk to ""seven year old child" not 6 or 8 years, which would fit with Nanatsu no Ko (Seven Children or Seven year old child). also hence why Nanatsu no Ko is favourite tune, also Crows metaphorically related to BO (as Raven), So TL;DR Nanatsu no Ko is the theme song of BO:lol:, BO members maybe fooled/ don't know true purpose of research yet, that'd make sense of APTX or Silver Bullet originally being top-secret forbidden immortality or anti-aging research
BTW: Akemi's PS to Akai Shuichi must be that "I have realized that I'm your sister/ cousin, would you still......?":rolleyes:
Also how the hell did Rumi got access to BO victims list in http://www.detectiveconanworld.com/wiki ... _Trip_Case