"Certain cell phone records of people who were associated with Cowell also are missing..."
http://www.wenatcheeworld.com/news/2010/apr/01/investigators-missing-cell-phone-data-in-cowell/
SPECULATION
I just had a thought about what Harum said in this interview. He talks about cell phone records of people associated with MC. It could be standard procedure, OR it could be that Harum just gave us a huge clue. I don't know if this has been brought up, but the fact that they're looking through cell phone records of people MC knew is kind of a big deal. I mean, the way I see it, this kind of tells me that this was not a serial killer or some random murder by a stranger. They've been looking into someone "associated" with MC, perhaps someone close to her.
Then again, it could mean nothing at all. Just thought I'd share my thoughts on this