I think what MysterySinger is getting at Pierre is that you posted:
A strong motive for the murders
A strong motive for taunting the police
A strong motive for spoiling Lord Mayor´s Day*
A personal motive for the choice of the 9th November*
*(these assumptions are not drawn from the metaphorical source I have discussed with you.)
One possible interpretation of this is that the three assumptions not starred with an asterisk ARE drawn from the metaphorical source you have discussed with us.
I don't think you actually meant to say that but perhaps you might like to confirm.