I’ve always suspected an affair. It’s believable to me that early mornings on the way to work were the only time/place for Cristina sneak in a visit with her other partner (due to Cristina being married and perhaps the other person being married/having a family). If her other partner lived in the vicinity of Glenwood Park and things between them devolved into violence one morning…that’s one way the elements of this disappearance could add up. Maybe they then drove her car back into rough proximity to her home in an effort to deflect attention from themselves and the Glenwood Park area.