A security guard was fatally shot by a police officer responding to a shooting early Sunday at a bar in south suburban Robbins. Four other people were wounded in the incident.

Just after 4 a.m., officers responded to a call of shots fired at Manny’s Blue Room Bar at 2911 S. Claire Blvd., according to Sophia Ansari, a spokeswoman for the Cook County sheriff’s office.

“Upon arrival officers learned there were several gunshot victims inside the bar,” Midlothian Police Chief Daniel Delaney said in statement.

One Midlothian officer entered the bar discharged their weapon at an armed man who later died at Christ Medical Center in Oak Lawn, Ansari said.

The man who died, 26-year-old Jemel Roberson, had been working security at the bar, according to Ansari and the Cook County medical examiner’s office. Roberson lived in the Homan Square neighborhood on the West Side.

An autopsy Monday found Roberson died of multiple gunshot wounds and his death was ruled a homicide, according to the medical examiner’s office.

Roberson was a 2010 graduate of Lane Tech College Prep High School on the North Side and played on the school’s basketball team, according to a post from the team’s Twitter account.

“We pass along our deepest condolences to the friends and family of Jemel,” the post read. “Jemel had a big smile and a bigger heart. You will be missed.”

Authorities released few details about the shooting, but said the incident started as an argument inside the bar, according to Robbins Police Chief Roy Wells, who spoke at a press conference Sunday morning.

Four other people in the bar suffered gunshots and were taken to Christ Medical Center in Oak Lawn and Metro South Hospital in Blue Island, Ansari said. Their injuries were not considered life-threatening—and it was not immediately clear who had shot them.

At least one of the wounded was considered to be a shooter during the initial incident, Ansari said. That person was in custody, but the sheriff’s office was not sure if there was an additional shooter in the incident.

Robbins police initially responded to the shooting and requested help from two Midlothian officers, according to Midlothian police.

The bar shooting was being investigated by the Cook County sheriff’s office. The shooting involving the Midlothian officer was being handled by Illinois State Police.

“It is the policy of the Midlothian Police Department to utilize the Illinois State Police Public Integrity Task Force for any officer-involved shootings so we can ensure transparency and maintain public trust,” Midlothian police said.