KANSAS CITY, MO. — A federal judge has released a police dash-cam video showing a Missouri police officer using force and a stun gun on a teenager who went into cardiac arrest.



Former Independence, Mo., Officer Timothy N. Runnels was sentenced last week to four years in federal prison after pleading guilty to violating the civil rights of 17-year-old Bryce Masters during a Sept. 14, 2014, traffic arrest. The video was played in court during Runnels' sentencing hearing, The Kansas City Star reported.



Police said Masters was uncooperative during the stop. The video shows Runnels instructing Masters to get out of the car, and Masters can be heard asking Runnels why and whether he is under arrest.



Runnels then can be seen trying to pull Masters out of the car and uses the stun gun on Masters, which continues to discharge for over 20 seconds. After Masters goes limp, Runnels can be seen handcuffing the teen and dragging him to the curb, where he drops him face down onto the pavement with a thud.