Murder, politics and dead ends

Recently, I had a conversation with a friend here in Arizona about the Stacey Burns murder case and my book. He happens to have extensive experience at the state level in a major crime unit in the Midwest (NOT IN N.H.) We touched on many different aspects of this sad story but three areas struck me as important-not necessarily new but important reminders as we enter the fourth year of the investigation.
1. Knowing only what I could tell him about the murder, he immediately said that whoever killed Stacey Burns must have really hated her. As Brad Garrett said in his 20/20 interview, this was "overkill." Maybe this is obvious to all but the savagery goes beyond simply killing someone.
2. Prosecutors have to be extremely careful. Much has been made of the double jeopardy issue and certainly no one wants to have a killer walk free because of a weakness in the case. Realistically, no prosecutor wants the political fallout from losing a case either. As my friend pointed out, any elected or even appointed official must be acutely aware of the power that placed them in office and they would not want to jeopardize that power base by losing what would surely be a high profile case. The political smart thing to do in the Stacey Burns case is wait and hope that something additional happens. Probable cause does not equal beyond a reasonable doubt.
3. Again, with just the knowledge that I shared with him, my law enforcement friend observed that the case is  probably at a dead end now. Three plus years is a long time. I wondered at what point does the killer say to himself (or herself) "I got away with it!"
Duker