An individual working private security at the Justin Beiber concert in Calgary on October 12, 2012 was hit by Justin Bieber. Justin Bieber tapped him on left shoulder while performing, and handed him a pair of sunglasses. The security individual gave these sunglasses to an excited fan..
Immediately following this Justin Bieber hit him on the left side of his head, and then pushed his head with his other hand. Both clips in this video confirm this story. Notice how Justin Bieber disguises this assault by ‘high fiving’ his fans immediately afterwards.
Timeline: 0:17 sunglasses in Bieber’s left hand 0:23 Bieber gives sunglasses to security guard 0:26 Bieber notices sunglasses given to a fan 0:28 Bieber hits security guard 0:44 slow motion hit from angle #1 1:38 slow motion hit from angle #2