Three generations of a family were killed Sunday when their SUV plunged more than 50 feet off of a highway and into a train yard next to the Bronx Zoo, killing all seven aboard.

Officials say they are trying to determine what caused the accident that claimed the lives of Jacob Nunez, 85, and Ana Julia Martinez, 81, their daughters, Maria Gonzalez, 45, and Maria Nunez, 39, and their three grandchildren.

Family members told MyFoxNY the family was only on a four-mile trip, from one sister's Bronx home to the other. The women's parents had arrived three days ago from the Dominican Republic for a month-long visit. The Associated Press reports the grandparents had 13 children total, six of whom lived in the US.

"I don't want to live any more. I want to die," Juan Gonzalez, Maria Gonzales' husband told The Associated Press.

Simon Torres, who identified himself to MyFoxNY as a brother-in-law of one of the victims, said relatives grew concerned when the family failed to arrive after half an hour. They then received a call from police.

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"It's crazy, seven people in one family? It's crazy," Torres told MyFoxNY. "Nobody feels good right now. It was a big family, you know."

MyFoxNY reports the accident scene rattled even the most seasoned firefighters and emergency responders, with one describing the injuries as "horrific and upsetting."

"I've been in the fire department 30 years, sometimes you come upon events that are horrific, and this was one of them," FDNY Deputy Chief Howard Sickler told MyFoxNY. "You see young kids hurt or lose their life it's always harder than when you find someone in an older age. It affects all our units."

Officials say Gonzales was driving the car, a 2004 Honda Pilot. The children were identified as Jocelyn Gonzalez, 10, the daughter of the driver, Niely Rosario, 7, and Marly Rosario, 3, both daughters of Nunez.

"They were a good, wholesome family," a Bronx neighbor, Felicia Lee, 29, told the Daily News. "The mother always kept an eye on her children. They were typical little girls. They were gorgeous. They were so pretty."

Police say the vehicle hit the median of the Bronx River Parkway, crossed traffic, then plunged more than 50 feet.

The vehicle lay mangled hours later, its right doors ripped off and strewn amid the trees along with items from the car. No zoo visitors were injured.

Fox News has learned that the train yard is where the zoo keeps its monorails overnight, when not in use.

The accident was the second in the past year where a car fell off the same stretch of the Bronx River Parkway. Last June, the driver of a sport utility vehicle heading north lost control and the SUV hit a divider, bounced through two lanes of traffic and fell 20 feet over a guardrail, landing on a pickup truck in a parking lot. The two people in the SUV were injured.

City agencies will be asked to look at safety issues on the highway including guardrail height, Bronx borough President Ruben Diaz Jr. said in a statement Sunday.

"My prayers, as well as those of my office and all Bronxites, go out to the families of the seven victims," he said.

Click here for more on this story from MyFoxNY.

The Associated Press contributed to this report.