(CNN) The Baltimore police officer caught on video punching a man for 12 seconds has "a history of antagonizing and aggravating" that same civilian, the man's attorney said Monday.

Warren Brown represents Dashawn McGrier, who got pummeled by the police officer Saturday morning . Brown said his client was arrested by the same officer in June and charged with assaulting the officer, disorderly conduct, obstructing and hindering, and resisting arrest.

A trial date for the case has been set for later this month.

The officer, Arthur Williams, was a newly sworn probationary officer, Baltimore police union president Gene S. Ryan said. Williams resigned after video of him beating McGrier spread rapidly on social media.

Brown said that during the June incident, his client was trying to restrain a young woman encountered by the officer. The cop then turned his ire to McGrier, grabbed him off a bicycle and threw him to the ground, the attorney said.

"This officer has a history of antagonizing and aggravating my client," Brown said.

CNN's attempts to reach Williams have not been successful.

When asked about the June incident, Baltimore Interim Police Commissioner Gary Tuggle said the man's contact with the officer resulted in his arrest. Tuggle noted there was no complaint filed by the man at the time.

Brown said his client also had an earlier encounter with the officer, who was "hassling" several young people weeks before. McGrier suggested "that they should talk to their parents about the way this officer is treating them," Brown said.

"This was personal. It was not professional. It wasn't probable cause or reasonable suspicion," Brown said of last week's encounter. "It was 'I'm the police and I have the power and ... I'm going to exercise that power,' albeit in an unprofessional, illegal manner."

Video of Saturday's attack shows a second officer watching Williams pummel McGrier but doing little to intervene . Police said that officer has been reassigned to administrative duties pending an investigation.

The state attorney's office has been notified, Baltimore police said.

What led up to the attack

The incident began around 11:45 a.m. Saturday while officers were working on "a crime suppression detail related to crime in the area," Baltimore police spokesman T. J. Smith said.

"Two officers encountered a man, whom one of the officers is familiar with," police said.

"After the first encounter, officers released him and ... approached him again to provide him a citizen's contact sheet," police said.

Smith said officers are required to fill out a contact sheet any time they talk to a citizen in relation to any type of investigation, no matter how brief the encounter.

"When he was asked for his identification, the situation escalated when he refused," police said.

What happened next

Bystanders capture video of McGrier screaming in the officer's face.

"For what?!" McGrier yells at Williams.

The officer responds by shoving the man backward against a brick wall.

"Don't touch me!" McGrier yells, slapping the cop's hand away.

Then the video gets really ugly.

The officer starts throwing punches and continues pummeling McGrier for the next 12 seconds.

Both men eventually fall to the ground and Williams pins McGrier down with his arm across his neck. McGrier's blood starts pooling on the sidewalk.

Brown said his client's injuries include a fractured jaw, but he should be released from a hospital on Monday.

"He's beat up. It's like as if ... you got tackled by (Brian) Urlacher or Ray Lewis or something," Brown referencing the former professional football players. "You're just a little guy ... and you can't defend yourself."

A city trying to recover

What happened this weekend marks the latest controversial use of force against a black person by police.

The Baltimore officer who attacked the man is also black. So is another officer who witnessed the attack.

The city is still dealing with the aftermath of the 2015 death of Freddie Gray, who died in custody a week after a police encounter . Days of peaceful protests over Gray's death devolved into riots, with assaults on police, looting, arson and the devastation of businesses.

A federal investigation eventually determined the Baltimore police department engaged in unconstitutional treatment of the city's black residents as well as excessive use of force.

In January 2017, the city agreed to a consent decree, with sweeping reforms proposed by the Justice Department.

After Saturday's attack, Tuggle suspended the officer before the officer resigned.

UPDATE:

The officer involved in yesterday's incident is no longer with the BPD. Interim Commissioner Tuggle has accepted his resignation. The second officer remains on administrative duties. This remains an active criminal investigation. — Baltimore Police (@BaltimorePolice) August 13, 2018

The acting police chief said he had "zero tolerance for behavior like I witnessed on the video."

"Officers have a responsibility and duty to control their emotions in the most stressful of situations," Tuggle said.

Statement from Interim @BaltimorePolice Commissioner Gary Tuggle on the viral video circulating online. https://t.co/3feuv9gU7E. pic.twitter.com/FJNlL8lzNj — T.J. Smith (@TJSmithMedia) August 11, 2018

The Baltimore Police Consent Decree Monitoring Team -- an arm of the US District Court for Maryland -- said it'll be closely watching how BPD responds to and investigates the incident.

"This is an important moment for the Baltimore Police Department," Consent Decree Monitor Kenneth L Thompson said in a statement.

Tuggle said all officers receive consent decree training, but that this situation shows a deficiency in their training.