While out in Barcelona, Justin Bieber has attacked one of his fans. He punched a fan in the face while his window was down in the moving vehicle. The punch was quite hard enough to make him bleed.
What triggered Bieber to punch the fan was when the fan stuck his hand in the window to touch him. Bieber responded with a quick jab to the face.
According to the video, the punched guy told friends he was going to punch Justin when he sees him. JB is seemingly having a track record of getting physical quite often.