Jennifer left for a first date. Hours later, her body was found on a busy highway road.

It was like any regular Friday night as Jennifer St. Clair readied herself for a first date with a man she’d met online.

Like many before her, she’d probably fussed over her hair, spent some time picking out an outfit, maybe even called a girlfriend to calm those inevitable first-date jitters.

But hours after packing her handbag, saying goodbye to her parents and hopping on the back of her date’s motorcycle, the 33-year-old’s lifeless body was found in the middle of a Florida highway, where she had died after being struck several times by oncoming traffic, as reported by US television station WPBF.

Now, witness statements suggest her date fled the scene on realising she had fallen from the back of the bike, leaving her for dead on the busy road – and leaving her grief-stricken relatives utterly shocked that someone could be so heartless.

“We don’t know how anybody could do something like that. It’s the hardest part,” Jennifer’s aunt, Amy Gamer, said at a news conference on Tuesday.

Her family, who are in the heartbreaking process of planning her funeral, say Jennifer was picked up by the man before heading out for dinner with others, who were also on bikes. The same bike, it is suspected, that witnesses saw leave the scene of Jennifer’s tragic end.

Jennifer's parents said goodbye to their 33-year-old daughter as she left for her date on the back of a motorcycle. Image: Facebook.

“Her family doesn’t know what happened,” Todd Falzone, her family's lawyer, tells PEOPLE. “They just know she was struck by many vehicles.”

“This is every parent’s worst nightmare,” Falzone said.

“It’s going to take a lot of work to figure out what happened, but we’re going to bring those accountable to justice.”

According to reports, Florida Highway Patrol officers responded to calls at 2am on Saturday, after a pedestrian had been hit by multiple cars.

Jennifer was pronounced dead on the scene.

One driver, who had hit Jennifer's body but had pulled over to wait for police, spoke to media on the scene.

“Laying across the road was what looked to be a body, and I couldn’t react in time and I ran it over,” he said. “I came to a stop as fast as I could.”

The man said he spoke with a motorcyclist parked in the emergency lane, who is believed to be Jennifer's date.

“I opened the door and asked, ‘Was that a person laying in the road?’" he recalled. “And he said, 'Yes, she’s dead.'"

Then, according to the man, the motorcyclist sped off.

Jennifer's family's lawyer says this story mirrors information from the highway patrol.

“He [Jennifer's date] pulled over to the median and did nothing to help her,” the man said. “The motorcyclist was fully aware of what was going on and left.”

While no arrests have been made, and no information released about the motorcyclist, The Miami Herald report that her death is being investigated as a traffic homicide.