One of the things that is often necessary is to reverse-engineer some of what LE knows but hasn't told us. You have seen some of this already with the mapping and isolating the exact or as close to exact as possible locations of Libby, Abby, BG, the various crime scene taped marked off areas, etc. You will also see where I have been trying to gather as much information related to the search (you will find the initial part of that in the scanner thread - more is coming later today from the ISP scanner traffic). There isn't much but it tells us much more than LE or media reported in terms of the activities going on and most importantly the time so we can get a better time line.
I know from my experience here the mapping sleuths and the photo analyst sleuths and flow of crime analysts (the crime, or puzzle pieces have to fit together and there usually is a flow) will still be working this - certain they may have missed something. Truly LE could save us some time, 100s of hours for some of us, but they choose not to do so for reasons I can't fathom considering that unless they have virtually little evidence there is much they could say about the time line, the crime scene, etc. that won't compromise the case. Even the audio recording may contain something else that is a quirk that would help someone identify the person speaking. For example, hypothetically, that person may, in only certain turns of phrase, use the wrong tense of a verb or the wrong form of the verb "to be" or they may have their own turn of phrase that is somewhat unique kind of like a catch-phrase. Who knows? LE wouldn't.
We are only at the end of the beginning of this, with a lot of work to do if we are to be of any assistance to LE. I know LE is hoping that the person that knows BG or the person that knows that voice will call in and tell the tip taker 10 details of the crime that haven't been released but that ship has sailed already. It is very likely that the persons LE is waiting for a call from do not consider they have enough information to even consider the person they live with or know to make a tip - which is a serious allegation of participating in a double homicide.
More information is better but it seems any time that the FBI gets involved in cases like this they hold back way too much information and when they finally do let something new out it has little value in generating useful tips because it requires people to remember seeing something that occurred or could have occurred 6,8 or 10 weeks prior and by that time most people won't be able remember what day in what week they might have seen anything related to that new information. They likely have boxes and boxes of information that they are hoarding and hiding like they have The Ark of the Covenant in their possession but truly has little value in getting to the killer sitting in those boxes. If their best and brightest haven't gotten to a strong suspect by now just based on the evidence alone they aren't going to get this solved on their own and the evidence is of little value to anyone until they get to someone - which may be never the way these kinds of cases are handled.