MIAMI -- Relatives of a UPS driver killed after robbery suspects took him hostage on a wild police chase across South Florida questioned Friday why officers had to unleash a torrent of gunfire when the truck got stuck in rush-hour traffic.

Both suspects, 41-year-old cousins Lamar Alexander and Ronnie Jerome Hill, were killed along with the driver, Frank Ordonez, and another motorist who was waiting at a busy intersection when officers ran up and opened fire from behind the cars of innocent bystanders.

The chase and final shootout were broadcast live on television, including the moment when one of the men tumbled out of the truck, mortally wounded.

Ordonez's family said the father of two was filling in on someone else's route Thursday when the robbery suspects commandeered his truck.

"I saw on TV when he fell, and I knew it was him. I saw how they killed my brother," Luis Ordonez told The Associated Press on Friday.

He said the "police were insane. Instead of talking to them, they just started shooting. I know they (the robbery suspects) were shooting back at them, but it was easy to just cover behind police cars. They could have just covered themselves."

News helicopters showed first responders tending to the person who fell from the truck, moments after the gunfire ended in Miramar, about 20 miles (32 kilometres) north of the jewelry store robbery.

FBI Special Agent in Charge George Piro was asked at a news conference Thursday night whether either the UPS driver or the other victim could've been killed by police bullets.

"It is very, very early on in the investigation, and it would be completely inappropriate to discuss that," Piro said. "We have just began to process the crime scene. As you can imagine, this is going to be a very complicated crime scene."

A fundraising appeal by Ordonez's brother Roy accused the officers of being "trigger happy" and said "they could have killed many more people."

Multiple agencies were involved in the chase and shootout. But Coral Gables Police Chief Ed Hudak suggested the blame belongs with the robbery suspects.

"This is what dangerous people do to get away," Hudak said. "And this is what people will do to avoid capture."

Thor Eells, executive director of the National Tactical Officers Association, said officers confronting the boxed-in UPS truck faced a tough situation. The robbers appeared to be firing at them, endangering not only Ordonez but dozens of people in surrounding cars. He said the officers had to stop the suspects by containing them to the UPS truck and returning fire.

"We have a situation with one hostage and the two suspects -- what happens if one of them runs 10 feet and takes over a city bus with 50 riders? Now we have a situation that is 50 times worse," Eells told the AP. Had the truck stopped in an isolated area, officers could have pulled back and negotiated, but not in the middle of a crowded street, he said.

It all started shortly after 4 p.m., when police in Coral Gables received a silent alarm at the Regent Jewelers store in the city's Miracle Mile area. Police said two suspects were at the store and shots were being fired when nearby police arrived, summoned by a silent alarm from inside the store. A store worker was hit in the head by a ricocheting bullet, police said. Another bullet hit a window at the Coral Gables City Hall.

The suspects carjacked Ordonez's delivery truck, leading officers on a chase into southern Broward County, running red lights and narrowly avoiding crashes. One rear door of the UPS truck was partly open, as well as the driver and passenger-side doors, enabling gunfire along the way. The UPS truck finally stopped in a middle lane at the busy intersection, caught behind a wall of other vehicles waiting for the light to turn green.

Katherine Gonzalez said officers were in front of her vehicle, a few feet away from the UPS truck, when the shootout started "out of nowhere."

"It was shocking," she said.

Both cousins have criminal histories: Court records show Alexander was sentenced to probation for a 1996 robbery and 1997 burglary. Five arrests in the 2000s resulted in no convictions before he served a lengthy stretch in prison for a 2008 armed robbery conviction in southwest Florida, gaining his release in 2017.

Florida Department of Corrections records show Hill served time in prison twice: in the 1990s on burglary and robbery convictions and more recently for five burglary-related convictions.

Naomi Hill, the aunt of both suspects, said Alexander was "a good boy -- he had changed his life around." She said he was married with three children and working for a garbage-collection company.

April Wyche, the sister of Ronnie Hill, said he was the father of two young children, one with special needs, and was working as a driver for a cabinetry company. She said she has no idea why he would have committed the robbery, saying he could have turned to her or their mother for help if needed. She wanted to apologize to the victims' families.

"No words can express how truly sorry we are," Wyche said, weeping. "We are praying for them."