An aide to Chicago Mayor Rahm Emanuel was punched, kicked and tackled by a pair of assailants on Sunday night during a vigil for two people who had been shot and killed by police.

“What are you doing here? You should be downtown doing something about this,” one of the attackers told Deputy Chief of Staff Vance Henry, according to the Chicago Tribune, which cited the police report.

The man also allegedly told Henry “the police are killing us” and made an anti-Semitic remark that the Tribune reported may have been directed at Emanuel, who is Jewish.

Henry, 50, who is black, was walking with a city alderman when he was accosted by two men. After the men made a few comments to Henry, they left – but returned a short time later and the episode escalated. When Henry told one of the unidentified men to “get out of his face,” the man punched Henry with a closed fist. The second man tackled Henry to the ground and the two men began kicking him. Eventually, the alderman stopped the beating and Henry drove himself to the hospital with minor injuries, the Tribune reported.

“We are aware that on Sunday afternoon there was an altercation involving one of our staff members,” City Hall spokesman Adam Collins said in a statement. “We take this matter very seriously and the incident is under review.”

No one is in custody for the assault, Sgt. Bob Kane told the Tribune. Henry knew at least one of the attackers “from a previous altercation,” the Chicago Sun-Times reported, citing a source.

Henry was attending a vigil for Bettie Jones, 55, and Quintonio LeGrier, 19, who were killed by Chicago police responding to a domestic disturbance call on Dec. 26. A police department statement said Jones “was accidently struck.”

Both Jones and LeGrief are black, and their deaths riled a community already wary of the police after video was released showing Chicago Police Officer Jason Van Dyke shooting a black 17-year-old 16 times during a 2014 incident.