BigAl, could you please clarify? I agree, the Rexburg PD/Sheriff definitely indicated that TD's death (or the investigation into TD's death) "could have ties" to the missing children, so I assume you are referring to the TD investigation (comments made around the time of the exhumation/ autopsy and/or the later property search in Salem)
But I had definitely been under the impression that both the earlier actions by Rexburg PD - first the wellness check done at Lori's town home on 11/26 (where I understood both Lori and CD were present), and then the search warrant(s) served the following day (11/27) by Rexburg PD at Lori's town home and the two nearby town homes (those reportedly belonging to AC and Lori's sister (or Melani?), respectively), had originated in, or been issued by, AZ LE/FBI.
I thought that perhaps the call from AZ LE/FBI to Rexburg PD on the morning of 11/27 regarding the ping that was "occurring right now" in the "general area" might have actually happened even as Rexburg PD were preparing to go to the location. Going a step further, I also wondered if maybe the use of the term "general location" perhaps allowed the search to be expanded from just Lori's town home to include AC's and the sister's (or Melani's) town homes, but that's all just conjecture on my part.
As far as who or what events in AZ might have spurred AZ LE's requests of Rexburg PD to do first the wellness check and then serve the warrant(s) at the Rexburg town homes, I think it was possibly due to a fast-growing concern and the mounting (and possibly linked) evidence from: CV's semi-dormant death investigation, possible information from CV's attorney(s), concern expressed by KVW and her husband about both CV's death and the whereabouts of the children, the attempted shooting of BB, the fact that no one had been able to contact the children since the 35 second FaceTime w/JJ, the fact that Tylee's SM had gone silent, and the fact that Lori, AC, Tylee, and JJ had rather abruptly left AZ (where all these events had recently transpired). Not sure how (or if) those AZ-based happenings or the earlier requests/warrants from AZ LE might relate to TD's exhumation/autopsy and the subsequent Daybell property search.