A federal civil rights lawsuit was filed against San Francisco police department for an incident of alleged police brutality against a young black man in the city in April.

The American Civil Liberties Union of Northern California and law firm Keker & Van Nest LLP announced the suit Wednesday following the April 10 incident when police allegedly unlawfully questioned, beat, detained and arrested Travis Hall, a 23-year-old graphic designer.

Police used excessive force and “sham charges” to detain Hall, said ACLU attorney Nayna Gupta, who is assigned to the case.

Hall was being dropped off at his home in San Francisco’s South of Market neighborhood when three undercover officers, Giselle Talkoff, Anthony Montoya and Joshua Cabillo, approached the vehicle containing Hall and three of his friends.

According to the ACLU, the officers began to aggressively question the four about their activities that evening and despite repeated inquiries as to why they were being detained, officers did not respond.

According to the ACLU, Hall became scared during the ordeal and attempted to call his mother, who is white and whose presence he believed would cause the officers to behave more respectfully and help them understand that he lives there.

It was then that Talkoff allegedly seized Hall from the car and threw him to the ground, causing him to hit his head on the concrete curb, according to the ACLU.

Officers allegedly slammed Hall on the ground with excessive force multiple times. Officers punched Hall, twisted his arm and threatened to break his arm, in addition to other threats, ACLU officials said.

Hall was arrested and transported to the Mission Police Station, where he was booked on suspicion of resisting arrest. His case was dropped by prosecutors shortly after the incident, according to the ACLU. Hall was released from custody the following morning.

Hall suffered a concussion and numerous cuts and bruises to his head, neck, face, and body, and suffered headaches for weeks. According to the ACLU, Hall’s injuries almost jeopardized his academic career and graduation from Fordham University, causing him severe emotional distress and anxiety.

“This was more than an abuse of power, it was against the law.  These officers cast an ugly shadow on the San Francisco Police Department, who they share a uniform with,” Hall said. “Police shouldn’t be able to do anything they want just because they’re in uniform.”

San Francisco police referred questions about the case to the city attorney’s office, which declined to comment because their office has not seen the lawsuit.

“No person should be treated the way that Travis Hall was treated,” attorney Ajay Krishnan said. “This was a traumatic event. SFPD had no probable cause. They did not say he acted violently or aggressively.”

According to a study by the W. Haywood Burns Institute released in June on San Francisco police activity in 2013, black adults are seven times as likely as white adults to be arrested in the city and 11 times as likely to be booked into jail.

“We’d like to see SFPD receive better training on implicit and racial bias,” Gupta said. “We’d like to see the use of body cameras on officers and robust demographic data collection.”

Earlier this year, several San Francisco police officers also came under fire for racist and homophobic texts, while police departments across the country are facing increased scrutiny for police brutality cases.

“Even San Francisco, which is supposedly an educated and progressive city, is just as vulnerable as other communities,” Hall’s mother Leigh Stackpole said. “Police brutality should not be a rite of passage for young black men.”

“What if they had slammed his head on the ground one more time or pulled a gun?” Stackpole said. “I would be one of those mothers protesting with only a photo of him rather than with him standing here next to me.”