I don't think the coffee thing sounds weird at all. We own a restaurant, and our coffeepot makes a LOT of coffee. There is no way I would make a whole carafe just for me, knowing that we weren't going to open for hours. And I can drink a whole pot at home alone!
I hope her BF didn't do it, and I think from what we know it is a huge leap to assume that he did. When I hear about the break-ins and robberies of restaurants and ice cream parlors and coffee shops in our very safe area in the 'burbs, it doesn't sound unreasonable to me at all to think that someone came to break in, surprised her and shot her, and then ran thinking someone might have heard the shot. Just b/c nothing was taken doesn't mean robbery wasn't the motive - they might not have finished what they started.
We had a break-in about a year ago. They threw a cement block through the front window of all of the stores in our strip mall. The place next door was robbed, but nothing was taken from our place or the one on the other side b/c we have an alarm (the only place that did!). That doesn't mean they didn't INTEND to rob us. Trust me, the $400 for the door was bad enough, and still is nothing compared to the loss of life in this case. It is one of my worst fears about owning the place.
Who knows how this will turn out, but I think jumping to the conclusion that the BF did it on this little bit of info is a little extreme.