OKLAHOMA CITY - A violent arrest from over the weekend was all captured on cellphone video.

Oklahoma City police pulled over a car driven by Dwayne Alexander near NE 23 and Hood for an expired tag.

According to arrest reports, Alexander also had a suspended driver's license, a gun and drugs in the car.

In the video, you see Alexander resist arrest before officers deploy a Taser on him.

Even though police say the arrest was justified, ACLU members say filming encounters like this is important.

“If you are in a negative or dangerous encounter with law enforcement you can’t call the police on the police. Your only option is to document your experience,” ACLU of Oklahoma spokeswoman Allie Shinn said.

Now, the ACLU said there's a way to use your smart phones to do just that with an app called "Mobile Justice."

The ACLU said they hope the app reverses a disturbing trend.

“An epidemic of over policing, of excessive force, of racial profiling, of communities across the country, but specifically communities of color. Too often police are going into communities of color and failing to serve those they are bound to protect,” Shinn said.

Police said it's completely legal to film these encounters.

"As long as they stay out of the police officer's way, there’s nothing wrong with that as long as you’re not impeding the officer from doing his or her job,” Oklahoma City police Capt. Paco Balderrama said

The police department said they internally investigate every use of force including the one involving Dwayne Alexander.

Since the app was released in May, the ACLU of Oklahoma has received 672 videos.