An SUV plunged into 20 to 25 feet of water.
A 14-year-old girl was pulled from the water and survived but five others inside that SUV all lost their lives.
The Mercury Mountaineer plunged into the water at Zimco marine in the Brownsville Shrimp Basin just before 4 p.m. Thursday.
"We could not see the car at all whatsoever, said Port of Brownsville Police Chief Carlos Garcia. It was pretty much all the way down."
Chief Garcia said a 50-year-old man, a 30-year-old woman and three children ages 10, 8 and 2 years old all died in the accident.
A shrimper at the scene rescued a 14-year-old from the water.
The teen is recovering at the Valley Regional Medical Center in Brownsville.
She's being treated for some light injuries but definitely seeing and talking to her, Chief Garcia said. She's very distraught about the situation."
It's not clear who was driving or what happened but Chief Garcia said the Cameron County Sheriff's Department is taking over the investigation.
The fatal accident happened while the SUV was being driven in the parking of a business at the shrimp basin.
The 50-year-old was expected to leave out to sea for shrimping season, which starts on July 15th.
They're hoping surveillance video can shed light on what happened.
"That's hopefully what the video will show, exactly how this happened, Chief Garcia said. Was it an error on the driver's party? Was it someone who was driving that wasn't licensed? Those are the things we're trying to find out first."
Even with two cranes, it took officials about two hours to get the SUV out of the water but by then it was too late.
Although a veteran law enforcement officer with decades of experience, Chief Garcia said the fatal accident was hard to process.
"The death of children is not easy, Chief Garcia said.
Sources at the scene told Action 4 News that the 2-year-old child was still strapped into a car seat at the time of the accident.
Cameron County Pct. 2-2 Justice of the Peace Erin H. Garcia ordered an autopsy for all five who died.
Authorities are not releasing the names of those who died in the fatal accident at this time but the accident remains under investigation.
Chief Garcia, who was once served a police chief for the City of Brownsville, thought fatal accident involving children were behind him at the Port Of Brownsville.
The veteran law enforcement officer held back tears as he told reporters what happened.
I never thought I had to see this again, Chief Garcia said. I thought my days of seeing something like this were gone|over."