I haven't followed this closely and may have missed important info, but I'm wondering if Ravenna and Cowen Parks (north of the U District) have been thoroughly searched? Those of you from Seattle will probably agree with me that this should be a no-brainer but I haven't heard that this happened. These are easy walking distance from the Safeway where Marizela made her purchases, and fairly heavily wooded with lots of natural plant growth, which in this area can be very thick and concealing.
Michelle Malkin mentions that Marizela left Safeway and headed "up" Brooklyn Avenue. To me this implies heading north, which would be straight toward Cowen Park.
Poor girl. This seems to be a very sad story.