As for current suspects, Spriggan is at the top of the list for me

. I think Bel gave really solid points surrounding his interrogation(if you want to call it that) of Takuan and Asako. Asking for their roles without even bothering to give a hint himself.
The saving Xadyu bit because Xad claimed Detective is expected, but it happened 2 minutes before the end of the DP and when Xad no longer needed saving so.....
Then there is Xadyu, you'd expect a claimed Detective to also be targeted, but he survived. Is it possible that Desin protected him, sure, but his hint was pretty ambiguous that we can't be sure he was a BG. Since Xad claimed already, guess we'll wait to see what he says.