There is no reason for the FBI to "assume jurisdiction." They can assist, advise, and get the evidence they need for a potential federal case while leaving PCSO in charge. Federal charges can always be filed later if a federal nexus is identified (and I'm sure it will be since the ransom demand and communication means involve the US financial system and telecommunications wires.)Something that hasn't gone unnoticed by me this whole case is that the FBI hasn't assumed jurisdiction. The only way they can do that here is if an abduction occurred and a component of the crime involved interstate commerce, or crossed state/national boundaries. So which of these two things is holding them up? For example, do they have strong evidence that NG was likely deceased prior to be removed from the home? Conversely, if they have compelling evidence that she was abducted and she was alive when removed from the home, then do they not already have evidence of interstate commerce via the ransom email(s) that almost certainly used proxy IPs that bounced through other states/countries?
So which component is restraining them? And which component is giving Pima county jurisdiction still?
These are important questions to ask, because the public has been given a ton of information alluding to an abduction and an as far untraceable (likely proxied/spoofed) ransom email, which implies federal jurisdiction, and yet Pima county still leads the investigation.
JMO.
I've defended PCSO although I agree and the sheriff admitted that mistakes have been made. But if the PCSO were screwing up in a way to compromise the investigation I think we'd see the FBI take over. That could certainly happen over the next few days and it would not surprise me. But for now I don't think there is anything to read into the PCSO staying in charge.