Two Guatemalan survivors of the 38 people found in a hot semi-trailer in a San Antonio Walmart parking lot said they were headed to Houston, officials said.

The apparent smuggling operation involving undocumented immigrants came to a tragic conclusion early Sunday morning when emergency responders found dozens of people in distress inside the trailer.

Related: What we know after 9 die from hot semi truck at S.A. Walmart

The death toll has risen to nine in the smuggling tragedy. Eight people were dead at the scene early Sunday morning. One more died during the day at a San Antonio hospital. Officials say that 17 of the 38 people found

are now facing life-threatening injuries.

When police arrived on the scene around 12:30 a.m. Sunday, they detained the driver immediately. The United States Attorney's Officer identified the driver as 60-year-old James Matthew Bradley Jr. of Clearwater, Florida. Bradley is being held in federal custody in connection with this incident.

Thomas Homan, acting director of U.S. Immigration and Customs Enforcement, said there may have been more than 100 people in the truck.

Mexican Consul General in San Antonio Reyna Torres says officials are working to identify the survivors and notify family members. Torres says the consulate has been in contact with relatives both in Mexico and the U.S.

Guatemala's foreign ministry, meanwhile, says at least two Guatemalans were on the abandoned rig.

Tekandi Paniagua, communications director for the foreign ministry, says the two male survivors told Guatemalan consulate officials that they crossed the border by foot at Laredo and boarded the tractor-trailer and that their final destination was supposed to be Houston.

According to the National Human Trafficking Resource Center, more than 670 human trafficking cases were reported in Texas in 2016.

Related: Lt. Gov. Dan Patrick weighs in after smuggling tragedy in S.A.

“It’s a humanitarian crisis, and in my view murder, when you stuff people when it's 100 degrees or more in the back of a truck. Who knows how long they were in that truck. I’ve always said, I’ve said this for years, no one should have to die to come to America,” said Lieutenant Governor Dan Patrick.

If you suspect human trafficking or smuggling, please report it by calling 1-866-347-2423.