Officer under investigation after punching teen

SEATTLE, WASHINGTON - (NBC) - A Seattle police officer is under investigation after punching a 17-year-old girl during a jaywalking arrest.

Video shot by a bystander shows the officer surrounded as he tries to issue jaywalking tickets to four young women.

The officer was attempting to handcuff one of the women when the 17-year-old pushed him away.

It appears that after a brief struggle, the officer punches the 17-year-old with a closed fist and then quickly moves in to handcuff her.

The video quickly went viral and sparked outrage among local civil rights groups.

Both young women are facing possible charges.

The Police Officers Guild in Seattle defends the officer's actions, calling them an appropriate use of force.

The officer is undergoing additional training while the investigation is underway.

Copyright 2010 NBC. All rights reserved.