Transcript for Family files lawsuit after bar security guard fatally shot by police
Next, to the protests and growing outrage over the death of a security guard who was holding down an alleged gunman when police arrived, an officer shot and killed the guard. ABC's erielle reshef back on the story tonight. Justice for jemel! Reporter: Growing calls for justice tonight after the shooting death of security guard jemel Roberson. He was one of the good guys. Had it not been for jemel Roberson, there would have been absolute carnage. Reporter: The family of the 26-year-old filing a lawsuit against the officer who gunned him down and the midlothian, Illinois, police department. Shots fired in the parking lot. Reporter: Witnesses say rober zone, an armed bouncer at a bar, had pinned down a shooting suspect until officers arrived. That's when one of them opened fire, killing Roberson. Police officer just saw a black man. I believe if he was indeed white he would be alive. Reporter: Tonight, that officer is on administrative leave. Roberson, a musician at local churches, was a new dad. He hoped to one day be a police officer. And David, while the incident is still under investigation, the police department says they are devastated, calling Roberson a great man who was doing his best to stop an active shooter.
This transcript has been automatically generated and may not be 100% accurate.