In cell phone video recorded early Saturday morning at North Avenue Beach in the city's Lincoln Park neighborhood, you can hear a woman screaming for help as she struggles with a CPD officer.
The woman's attorney said the altercation began after the officer seen in the video allegedly asks the woman to leave the beach because it was closed.
Following that order, you can see an altercation between the two.
WATCH: Video shows altercation between CPD officer, Black woman walking dog
Videos show altercation between CPD officer, Black woman walking dog
"For some reason, this officer decided to specifically interact, and then ultimately address and attack Ms. Brown," said Keenan Saulter, the woman's attorney.
Saulter identified the woman as Nikkita Brown and said she is traumatized from the encounter.
Her lawyer called the incident a brutal and unprovoked attack, saying that she was leaving the beach when the officer put his hands on her.
"She was always in the process of leaving," he said. " She was always walking out of the park."
The Chicago Police Department responded to the video, saying in a tweet that they are aware of the video and are working with the Citizen's Office of Police Accountability on the matter.
COPA said in a separate tweet that they are working with Brown's attorney.
"We absolutely want a full investigation," Saulter said. "Our challenge is, we want this officer identified so we can formally make a complaint."
Brown's lawyer said she called 911 when she made it back home, claiming that she told a CPD sergeant the altercation started while the officer was in his squad car.
Brown added that other people were walking out on the beach at the same time, but feels she was targeted because of her race.