The officer's name is know known to be Daniel L Andrew, he's had previous run ins with the woman he punched the shit out of, and still hasn't been fired http://losangeles.cbslocal.com/2014/07/26/new-details-emerge-in-beating-of-homeless-woman-by-chp-officer/
it's evidently not as rare as you'll likely hear the CHP pretend it is http://news.msn.com/crime-justice/surveillance-tape-shows-police-punching-suspect
and today on the AM 1070 LA radio station KNX it was reported that a federal case is now filed as the CHP have dragged their feet since July 1st, and not completed what they term, an "investigation" http://wavenewspapers.com/opinion/article_52758f56-1368-11e4-8d90-0017a43b2370.html
The U.S. Attorney's civil rights division has been prompted to open a formal investigation into the "slow pace" of the CHP investigation and a lack of transparency in the investigation including shielding of the officer’s identity. The CHP, "have further reinforced our lack of confidence" in the investigation. Pinnock has filed a federal civil rights lawsuit against the officer and CHP Commissioner Joe Farrow, alleging the officer used excessive force.
http://www.latimes.com/local/lanow/la-me-ln-civil-rights-probe-chp-beating-20140729-story.html
And then there is fat Frank Phillips, Knox County Sheriffs officer who chokes a non-resisting drunk college student
Frank was photographed using excessive force and violating the rights of the student, and promptly got fired when the photos were published, and they didn't correspond to the bullshit in the police report that the drunk had resisted arrest. http://www.washingtonpost.com/news/morning-mix/wp/2014/04/28/knoxville-cop-fired-immediately-after-photos-show-brutal-choking-of-student/