By Kevin Murphy
KANSAS CITY Mo. (Reuters) - The FBI is investigating allegations of excessive force by a Missouri police officer during a traffic stop that left a teenage motorist in critical condition, authorities said on Monday.
The FBI said in a statement that it is investigating whether police officer Tim Runnels overstepped his authority and violated the civil rights of Bryce Masters when he pulled over the 17-year-old and used a stun gun on him on Sunday in Independence, Missouri, a Kansas City suburb.
The incident comes five weeks after a white officer in Ferguson, Missouri fatally shot an unarmed black teenager, sparking racial unrest and highlighting concern about the use of force by police.
Runnels used a stun gun on Masters after he did not cooperate when his vehicle was stopped, Paul Thurman, an Independence Police Department spokesman, said during a news conference on Monday.
Thurman said there was an altercation between Masters and Runnels outside the car, prompting the use of the stun gun, but did not elaborate on what happened.
Thurman and Masters are both white.
Witnesses told the Kansas City Star that Masters was unable to roll down his window because it was broken and that after handcuffing Masters outside the car, Runnels dropped him on the pavement, causing him to injure his head.
Masters was taken to a hospital, where he remained in critical condition in the intensive care unit, Thurman said.
The lawyer representing the Masters family, Daniel Haus, said in a statement they requested a civil rights investigation because of "significant inconsistencies" between police accounts of the incident and evidence presented by witnesses and in video.
Runnels, who was placed on administrative leave, followed policy in using a stun gun on Masters after he became uncooperative, according to Thurman.
Masters was stopped because the car he was driving was registered to a woman who had an outstanding warrant, Thurman said, adding that she was not in the vehicle.
(Editing by Brendan O'Brien and Eric Walsh)