(CNN) -- Brenda Cruz and her family were flabbergasted by what they spotted as they were driving on Interstate 77 in North Carolina this weekend:
A man was hanging on to the back of a fast-moving white sedan in the right-hand lane.
"All of a sudden the kids say, 'There's someone on top of the car on the trunk,' and I'm like, 'What?'" Brenda Cruz told CNN affiliate WSOC.
The man was lying across the outside of the car's trunk, she said, as the vehicle sped along at around 50 mph Saturday afternoon.
She pulled out her cell phone and began to film the bizarre scene as other cars on the road slowed down, waiting to see what would happen.
The family said they witnessed the man shattering the rear windshield before clambering inside the moving vehicle, which was being driven by a woman and had a child in a car seat inside.
"Whenever he lifted his hand to smash the glass open, it looked like it was something sharp," Brenda's 17-year-old son, Samuel, told WSOC, saying he was concerned about what might have happened next.
"I'm really worried because I just hope she's OK, you know, with her kid," he said.
Authorities said Monday that the incident began as a domestic dispute at a nearby Payless ShoeSource and continued on the highway.
"The female driver is the victim and will not be charged," said Keith Trietley, spokesman for the Charlotte-Mecklenburg Police Department. "She chose not to prosecute the male suspect. They are known to one another and were involved in a domestic dispute. No one was injured during the incident."
Trietley declined to identify the couple, noting that no charges have been filed.
CNN's Matthew Stucker contributed to this report.