Found the video source for the following picture:
This video establishes the position of this officer as well as shows his identification.
I do not have the skills or the computer to do frame by frame analysis for you but if you watch carefully especially noting the height of these officers you too can easily percive a sequence of events. Or not depending on your viewpoint.
This is who is being accused:
I would like to thank mahakali overdrive for doing the leg work in finding out the following information.
From Tweets:
OccupyMARINES : SFSD ESU Officer Yambao Stood Next To Officer Bergstresser And Did Nothing In Response To Olsen's Injury
7 hours ago 2 Retweets
OccupyMARINES
OccupyMARINES : SFSD ESU Officer Bergstresser. We Are Sure There Is A history With This Man And Are Looking Into It Further
5:47 PM PT: Video of the police line here 1:40 in:
http://www.ktvu.com/...
9:08 PM PT: Ralph Lopez's diary corroborating this assertion:
http://www.dailykos.com/...