Her car was found at MOA?
I'm from Minneapolis, and while the mall is definitely continued safe, there are many sketchy characters there that just hang out throughout the day. As it is open early in the morning until late at night, and is so big and only so many police officers, it is an easy place for sketchy characters to be and to disappear. The new light rail train comes from downtown directly to the mall now, and since then I have noticed an increase in the amount of people there that I consider sketchy.
She very well could have met unsavory characters in the mall itself, or in the parking lot. The parking lots are huge and dark and honestly it wouldn't be hard to mug someone in the parking lot or rape them or take them. I am sure there are cameras but it is dark. Or I hate to say it, she could have gone there to seek out these characters (maybe drugs??) and had something happen to her.
What about cameras? Do they have footage of her in the mall at all? I am serious when I say the place is so big, someone could easily be lost in there if they fell and hurt themselves.
ETA - Just looked at her facebook. Despite being married, no profile pics have her husband in them (that are clearly identified. One she is with a man, but they're wearing costumes and I don't see a ring). That is odd to me. That might bring a new angle to the case. People in happy relationships show it off, she hasn't.