Just to give a fuller picture of the event...

The initial exchange is not on video (or has not been released). The available videos show that Rosenbaum chases Rittenhouse and throws a plastic bag at him (which did not hit Rittenhouse). Rittenhouse fires a shot and Rosenbaum reaches to disarm Rittenhouse. Rittenhouse fires four more shots, killing Rosenbaum (he was found with wounds to the back, thigh, groin, hand, and a graze to the forehead). Rittenhouse circled back to Rosenbaum as someone else arrived to assist him. Rosenbaum made a phone call to his friend about what he'd done, then fled the scene. Witnesses and bystanders then followed Rittenhouse, and some attempted to disarm him. Rittenhouse fired at them, killing one and injuring another. Rittenhouse walked toward, then past police, and escaped, only to be arrested later.