http://www.huffingtonpost.com/entry/brother-missing-mom-fails-polygraph_56268a4be4b08589ef493cda
Forget about Brook Houck for just a few minutes, look at the highlighted areas above, which are all in relation to
Nick Houck. It's obvious that he is knee deep in this thing.
To me it looks like they're inferring that Nick Houck had Crystals body in the back of his police cruiser for an uncertain amount of time. Apparently they didn't get traces of blood, but instead got traces of other bodily fluids, although it is unclear what those may be ( to me) . It appears to me that this would indicate she was strangled or choked to death, which would result in no blood loss to speak of.
These two guys were in on this thing together, sort of like a Leopold and Loeb team , "Let's commit the perfect crime, and show ourselves and everybody else how smart we are".
I don't know that this was a planned event so much as a domestic violence incident that went terribly wrong, and then the two brothers together worked as a team to cover it up. It's also entirely possible that they were both there when she was killed.
That phone call during the interview appears to be totally
staged, with Brook Houck using it as a springboard to once again proclaim his innocence and further complain about the cops harassing him. Nick Houck would've been well aware that his brother was going to be going in for an interview with the investigators, in advance of going. That phone call in the middle of the interview wasn't a mistake, if anything, it was Nick Houcks nerves being on edge because he knew his half-wit brother was sitting down for an interview and he didn't want the threads of deceit to start unraveling.