I have the same questions.
There must be something more to this. IIRC, she had some kind of ‘prior’ that may be had some influence.
http://theconservativetreehouse.com/2015/07/23/sandra-bland-had-long-history-of-drivinglegal-infractions-family-who-refused-to-assist-with-bail-now-refusing-to-accept-suicide/