I am almost 100% certain they know who BG is, and I think there is good information out there that cuts down the pool of possible persons fairly narrowly, which I would love to get into here, without naming full names. The entire strategy of ISP since at least 2019 (and probably much before that) has been focused on the community itself, the search party -- even though they will not come out and say it directly -- and individuals they have interviewed before. I also think the circumstances point to more than one individual involved, and in my opinion, there are at least two with up to four or five principal actors in the murders, with more possibly involved peripherally.
IMO The KAK/TK push in the last few months is a controlled leak by law enforcement. I do believe they have involvement in what transpired on 2/13-14, but they are being used as a smokescreen to throw off (even if subtly) their main POIs. It is my opinion that KAK has turned state's witness, possibly much before the August 2020 charges and arrest. The well-known podcast group that broke the stories, along with the more mainstream NewsNation, are a part of this operation by ISP. I have written a bit about this elsewhere and would be willing to share more on this forum if there is interest, as I have just signed up here after reading for a while. I do not have any inside information, just a synthesis of public knowledge that I believe points in this direction