I feel that whatever happened to Caylee was at the hands of Casey, but without a crime scene showing major blood loss, a body with trauma, or something like that, I do not see how I could be able to rightfully convict for anything other than negligent homicide or a manslaughter.
If the trunk evidence comes back showing Caylee's DNA from the cadaver fluids, then it would prove Caylee has died. It would not prove, beyond a reasonable doubt, how she died. If she died from a hot car, accidental drowning, or something else, the prosecution has to prove beyond a reasonable doubt that it was 1st degree murder, 2nd degree murder, homicide or manslaughter.
When I listened to the phone calls, Casey sounded like one of the coldest, self-centered people around. I justl don't think that would be enough to convict her of 1st or 2nd degree murder. I would need proof of trauma. And, without trauma, I would have to go for a lesser charge of homicide.
Hopefully, LE will take their time to build up very substantial evidence to prove beyond reasonable doubt that a murder was committed.