A California Highway Patrol officer straddles the woman on a Los Angeles freeway while punching her in the head
Media playback is unsupported on your device

US policeman 'seen hitting' woman in California

5 July 2014 Last updated at 16:29 BST

The California Highway Patrol says that it is investigating footage posted on YouTube that shows a policeman repeatedly punching the face and head of a prostrate woman.

Police say that the woman needed to be restrained and was endangering herself and motorists by walking on a busy road in the west of Los Angeles.

Chris Rogers reports.