From [HERE] Police have launched an internal investigation after a video was posted online that shows an officer striking a woman twice in the face at a neighborhood party associated with Philadelphia's annual Puerto Rican Day parade. The 36-second video uploaded to YouTube and titled "Philadelphia Police Brutality" shows the woman crumpling to the ground after being struck Sunday in north Philadelphia. The woman appears to be bleeding from the mouth as she is led away in handcuffs. In the video the officer comes up from behind her and as she turns and looks at him he hits her with his right fist. She drops to the street - other officers watched. Was this technique in the police training manual? 

Moments before the woman was hit, the video shows someone else throwing a liquid toward the officers. The woman was also seen spraying something from a can. The woman, whose name was not released, was cited for disorderly conduct, said Officer Tanya Little, a police spokeswoman.