When you're stuck and pieces aren't fitting into place, an enlightening exercise can be to assume the opposite of what you believe and play it out logically to see if any pieces suddenly fit. Even basic stuff like, "Who has Libby's cell phone?"
I (still) believe LE recovered her phone, but realized tonight that's an assumption most of us have made without having any confirmation that it's true. Here and there in these threads people have asked about it, but there has never been much discussion because it hasn't seemed important if LE got video from the phone itself or the cloud. But what if you start with the assumption that LE does NOT have the phone, and then play it out?
We know Libby had her phone on her at the time of the abduction, but now we'll assume they cant find it. The phone was "pinging around town" until around the time they were reported missing. If you can get BG to turn the phone back on, you can get it to ping again and figure out a location. But how to get him to turn it back on? Release a couple grainy video stills of a POI and reference that you have a lot more video...make BG wonder if there was something captured on the phone that provides more evidence as to who he is...make him want to stay a step ahead of LE by turning on the phone to find out what all Libby recorded. That could be why they just said he was someone they wanted to talk to early, and not a POI or not definitely involved...he's less likely to turn it on if he knows LE has fingered him for the crime.
Let's say this did work in the first few days, and the phone did ping briefly. That would be enough PC to get a SW if you had a precise location. But if it was just a general area? Then maybe you look for an RSO in that area, and get a SW for their house. This could explain the Bicycle Road search that turned up nothing (and it at least helps me understand where a lot of people leaving cryptic comments about the phone pinging at that house lately are coming from).
Or maybe it pinged in that area before it shut off for a final time on February 13, and that's why they served the SW there. And maybe the efforts to get BG to turn on the phone have failed so far. If that's the case, it would explain ISP Supt. Carter's statement last week that they are still waiting for a specific piece of intel to come in, and they know it isn't in the 13,000 tips that have been called in. And it would also explain why many feel like the case has gone cold.
That's about as far as I've taken it so far, and I still believe they have her physical phone. But I'm less confident in that assumption now, because it does seem to make some events/statements "fit" better. Anyway, hope that line of thought/type of exercise helps those of you better at this than me to come up with some good new theories.