A UPS driver and an innocent bystander were also fatally shot during the gun battle in Miramar, which was seen on local TV.
The FBI identified the robbers as Lamar Alexander and Ronnie Hill, both 41, WPLG-TV reported.
"He just made bad decisions in life and it cost him his," Corey Smith said of Alexander, who was his brother, according to the station.
Alexander was a felon with a lengthy rap sheet, including armed robbery, according to the station.
Florida Department of Corrections records show Alexander was convicted of robbery with a deadly weapon in Lee County in 2009, the station reported. He was sentenced to 10 years in prison and released in 2017.
Hill was also released from prison in 2017, WPLG reported. He had a series of convictions for burglary and robbery.
The shootout took place after Alexander and Hill robbed a Coral Gables jewelry store and then hijacked a UPS truck during the getaway.
The UPS driver who was killed had been identified as Frank Ordonez, a 27-year-old man with two young daughters, according to reports.
It was not immediately clear who fired the shots that killed Ordonez or the bystander.
News helicopters were following the chase and at least one showed the conclusion live, with one person falling out of the vehicle’s passenger side after several shots were fired.
“It’s very early in the investigative process,” FBI Special Agent in Charge George Piro said Thursday night. “There are a lot of questions that are still unanswered.”
The Associated Press contributed to this report.