Why hasn't Drew Peterson been charged with the death of his 3rd wife?

Question

His third wife's death was ruled a homicide. They determined that she was killed and her body was staged to look like an accident, and Drew Peterson has yet to be charged with her death. Why hasn't he been charged? (I'm not really looking for "because he got away with it, he has a good lawyer, he's a white cop" etc)

I searched around on CNN, Wikipedia, and Google news but it never really says why. I know they are focused on finding his last wife but why don't they charge him with the death of his other wife?

http://edition.cnn.com/2008/CRIME/02/21/missing.wife/index.html#cnnSTCText

Answer 1

I agree with the previous answer.  It will happen.

Answer 2

The police do not have sufficient, or irrefutable evidence at this point to charge, and hold him.

It will happen.