On the afternoon of September 29 in Allentown, Penn., according to police, a group of high school students who'd just been released from school were moving so slowly while crossing the street that they'd stopped traffic. Officer Jason Ammary attempted to deal with this pressing issue by "issuing verbal commands"; when that was unsuccessful, he approached a 14-year-old student named Keshana Wilson to "get [her] to move along." Ammary says she began to curse at him, "inciting the crowd," which Ammary determined to be an arrestable offense. This is where this video, taken by closed-circuit TV and obtained by the Allentown Morning Call, begins, more or less. (It's missing nearly a minute of footage, for reasons that are unclear.)
Wilson's mother is suing Ammary and the police department for use of excessive force. As is clear in the video above, Wilson put her hands up before Ammary fired the taser; furthermore, the suit claims, Ammary "grabbed Wilson from behind without identifying himself [...] 'violently' pushed her into the side of a parked vehicle [...and] placed his right forearm against her throat, choking her." The police department claims that Ammary was justified in his use of force.