I am honestly a fence-sitter, but do have a couple of relevant points re this topic:
The cadaver dogs - there are circumstances where they falsely hit, here are a couple of links to read about that.
http://www.k9fleck.org/articles/cadaver_dog.html
http://www.k9forensic.org/AAFSpaper.html - cadaver dog
The stain in the trunk: If the stain in the trunk were definitely decomp., wouldn't there be a homicide investigation, with or without a suspect? I understand about the speedy trial and discovery, but can't LE conduct a H.I. without arresting Casey first?
There would be no need for air testing if the stain was definitely decomp. Any body fluid yields DNA, although possibly degraded due to environmental conditions - the fluid itself would decompose, and doesn't necessarily indicate the person was dead. I hesitate to mention this, because I can't say it without doubt, but I thought I heard one of the spokespersons mention the stain contained amylase. I can't find it now, but another poster thought they heard something similar, mentioning epithilial cells, I don't think they found it either. This to me suggests vomit, which can go its own direction re chloroform.
I'm also new and a very slow poster, so pardon if I'm butting in somewhere.