A video which has gone viral on social media shows a black man in prom attire being choked by a police officer and slammed to the ground.
"We are now investigating the whole incident, interviewing witnesses and gathering additional video", Southerland said in the statement.
Speaking to ABC 11, Wall explained that he was at the restaurant to get some food after taking his 16-year-old sister to prom.
Furthermore, conventional wisdom around police brutality against African-American males would tell us that there was probably a very minor reason, if any at all, that the officer resorted to putting Wall in a chokehold.
Wall was charged with disorderly conduct and resisting arrest, ABC11 reports.
The Washington Post reported earlier, officers in Saraland, Alabama, wrestled a black woman to the ground at a Waffle House, exposing her breasts in the process:"The video shows Chikesia Clemons, 25, sitting on a chair at the diner as one of the officers grabs her neck and right wrist in an attempt to subdue her. Clemons describes a disagreement with a store employee that triggered the police response".
The footage shows 22-year-old Anthony Wall being violently restrained and arrested after getting into an argument with several employees, which resulted in police being called to the location.
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"We're once again outraged by a video showing police officers using excessive force on an unarmed, non-violent African-American Waffle House customer", said Sherrilyn Ifill, President and Director-Counsel of the NAACP Legal Defense and Educational Fund, Inc.
"I was pretty much trying to scream for air and trying to breathe because he was holding my throat and that's when I got aggressive with him because you are choking me", Wall said.
Wall says his back was injured and he had a cut on his arm. The department also informed the local District Attorney of the investigation.
"Your hands should have never been around my neck like that if my hands was in the air", he continued.
When asked if the officer's behavior in the video reflects what Warsaw officers are trained to do in such situations, Southerland said "no".
Details are not known on what prompted the use of force.
"I wish people would not blow things out of proportion and not let one situation create any additional situations", Southerland said.