Chicago police officer fatally shoots a black security guard who was detaining a suspected gunman at a bar.

Yet another  black man gunned down, what more can the black community in america be forced to swallow? Authorities on Monday were trying to put  together how a suburban Chicago police officer ended up fatally shooting a black security guard who was detaining a suspected gunman who opened fire at the bar where he worked moments earlier.

Jemel Roberson, 26-year-old armed guard, a man of african descent, was pinning down the suspect outside Manny’s Blue Room in Robbins, Illinois, early Sunday when an officer posted to the scene opened fire on him, according to witnesses and a federal lawsuit filed Monday by Roberson’s mother.

Witnesses  believe the officer, who works for the neighboring Midlothian Police Department, may have acted impulsively upon seeing an armed black man when he arrived at the scene.

witnesses further talked about  the fact that the police officer was notified by bystanders about who jamel was as “Everybody was screaming out, ‘He was a security guard,’  but unfortunately, they basically saw a black man with a gun and killed him,” witness Adam Harris told WGN-TV.

Officials said Roberson had been working at the bar early Sunday morning when a dispute involving several men broke out, leading to gunfire inside the bar.

The incident got out of hand when one of the men opened fire inside the bar around 4 a.m., according to Sam Randall, a Cook County Sheriff’s Office spokesman. A lawsuit filed by Roberson’s mother, Beatrice Roberson, on Monday alleges that “some patrons” shot the bartenders and others.

The lawsuit also alleges the officer used “unprovoked” and “excessive” force in fatally shooting Roberson. Beatrice Roberson is seeking more than $1 million in damages from the village of Midlothian and the officer, who is identified as John Doe in the complaint.

“The shooting of the decedent Jemel Roberson was unreasonable,” the lawsuit alleges.

Midlothian Police Chief Daniel Delaney said in a statement that officers responding to the shooting found multiple victims inside the bar. Midlothian police as well as the Cook County Sheriff’s Office were asked by Robbins Police to dispatch officers to the scene.

Delaney noted the “Midlothian officer encountered a subject with a gun” before discharging his weapon. In addition to Roberson, four others—including the suspected gunman—were shot during the incident.

The incident comes more than a month after former Chicago police officer Jason Van Dyke was found guilty by a jury of second-degree battery and aggravated battery for the 2014 shooting death of Laquan McDonald. That controversial incident — police video showed McDonald was armed with a small knife but was walking away from police when Van Dyke fired 16 times —spurred protest and political tumult in the nation’s third-largest city.

Rev. Michael Pfleger, a Chicago pastor and civil rights leader, said the Midlothian officer “must face the same consequence as Van Dyke.”

“He must be Indicted…..and White Society’s “Fear of Black Men” must END!!!!” Pfleger posted on Twitter.

The Illinois State Police Public Integrity Taskforce is conducting an investigation of the officer-involved shooting, while the sheriff’s office was investigating the shooting inside the bar. The suspect, who was shot at some point inside the bar, remained hospitalized Monday and had not been charged.

The circumstances of Roberson’s shooting spurred anger as well as sympathy.

A GoFundMe page to help his family pay for funeral costs had collected more than $20,000 as of late Monday.