Re: LE & secrecy, I totally get it. I never expect them to show their hands while the game is still in play.
But what I have found strange from the offset of this case is the lack of pressers and statements. Even something as simple as, "We're still working on this. We'd like to thank the public for all the tips.... etc." While it's not necessary, particularly helpful, or something they owe the public, it's something I'm accustomed to seeing.
I definitely feel that, even though this crime might be centered around just this family, it's part of a spiderweb of criminal activity. I think that this case is likely tangentially linked to other cases, or is pertinent to a larger case. I can't really think of another reason why LE would be this tight lipped.