The use of tasers by law enforcement is becoming increasingly controversial as more examples emerge of them being used improperly and causing victims serious harm. This New Mexico teen was arguing with her mother, so her mother brought her to a police station to get help (it's unclear what kind of argument they could have been having that would warrant police intervention).
The girl ran off and the police chief chased her and ordered her to stop. When she didn't, he tasered her in the head. The giant scar and stitches in the teen's head show the tasering was terribly brutal, and it's difficult to see how this could in any way be justified.