>> stop. [ muted ]. oh [ muted ]. he's beating her up. >> my gosh, why? >> just blow after blow caught on camera. now the california trooper you see here is off the street, on administrative leave, while his actions are under investigation. cnn's sarah sidener has the story. >> video from a california freeway shot by a driver stunned by what he was seeing unfold. a woman being punched over and over and over again by a california highway patrolman. >> you see it, you heard it, you're like, thump, thump, thump! then you hear her head bouncing bam, bam, on the concrete. >> how many times did he hit her? >> i seen 11 on the video. he took more shots than that. i think around 15 shots. to her head. and then -- >> punching? >> punching. this is not just jabs. these are hooks. lights-out punches. those aren't taps.