LOL, what does LE know? By this time they know who she was calling for the last several months, who she was texting and sexting with (and how often and what was said), they know who she was spending her time with and how she was spending her time and how she was spending her money. They probably also know if she was spending time on the computer and who with.
They know where she went and how often. And they know who she talked to just prior to and just after Kyron's disappearance as well as where she really went (Phone GPS).
Not only that they have also done checks and spoken with the people she has spoken with with, spent time with or had connections to.
If you spent any time in the Caylee forum during the early days and viewed any of the docs that came out, you would have some idea of how much they know. But exactly what they found out, how they interpet it, and what it means is a different story. How much of it is useful and how much is just normal living activity is unknown.
Yeah, just because LE isn't talking doesn't mean they don't have anything. They always know much more than they are telling. And often what they say in a PR media interview has double meanings. (IE yes the subject is cooperating. sometimes means yes, the subject talked to us but no we don't believe what the subject said to us.)