Police in San Antonio discovered the bodies of eight illegal aliens in a tractor trailer parked in a Walmart parking lot early Sunday morning. A nineth man died later from exposure to the heat and lack of water. Approximately 20 persons were in “extremely critical” or “very serious” condition.

Update 4:00 p.m.: Officials with the Department of Justice Western District of Texas reported the number of deaths from this incident rose to nine. The deceased victims have only been identified as adult males. All other information about the illegal immigrants is being withheld pending notification of family members.

The total count of people being smuggled in the trailer also rose to 39. Officials stated that police found another individual hiding in the woods near the trailer parked in the Walmart parking lot.

The U.S. Attorney’s office in San Antonio identified the driver as James Mathew Bradley, Jr., 60. He is a Clearwater, Florida, resident. Bradley is in custody pending charges expected to be filed on Monday. He is also expected to appear in court Monday morning.

The air conditioner was not working in the trailer. Many of those found had heart rates of over 130 beats per minute and suffered from heat stroke. More causalities are expected, officials stated. Thirty-eight people were in the trailer. Two of those were school age children. In total, police found 38 people in and around the trailer.

Police apprehended the driver of the truck at the scene.

Walmart employees become aware of the situation after one of the aliens approached them and asked for water. Police arrived at the scene shortly after midnight Sunday morning, KENS5 reported. At least 29 fire rescue units arrived at the scene and two AirLIFE helicopters assisted in transporting the most critically ill patients.

Others in the trailer survived long enough to be rescued and taken to a local hospital. Those included two 15-year-old juveniles.

Surveillance cameras showed a number of automobiles coming to pick up persons in the trailer. Authorities suspect a human smuggling operation.

Officials in San Antonio said that they are working with the U.S. Department of Homeland Security.

Breitbart Texas obtained a statement from U.S. Attorney Richard L. Durbin, Jr. with the U.S. Attorney’s Office, Western District of Texas. Durbin said:

San Antonio firefighters and police responded to a horrific scene this morning on the southwest side of town. They discovered an alien smuggling venture gone horribly wrong. Eight immigrants were found dead. At least twenty more were in serious condition. All were victims of ruthless human smugglers indifferent to the wellbeing of their fragile cargo. The South Texas heat is punishing this time of year. These people were helpless in the hands of their transporters. Imagine their suffering, trapped in a stifling trailer in 100-plus degree heat. The driver is in custody and will be charged. We will work with the Homeland Security Investigations and the local responders to identify those who were responsible for this tragedy.

Authorities said they would be checking nearby woods again for those who may have gotten out of the trailer on Sunday morning. They will also be reviewing surveillance tapes.

The San Antonio Fire Department released the following statement:

Shortly after 12:30AM (Central) the San Antonio Fire Department responded to 8358 IH-35 S. for a report of multiple people in the trailer portion of an 18 wheeler. First arriving units found a number of people in the back of this trailer all in varying degrees of medical distress. A total of 8 individuals were deceased upon our arrival. 17 patients were transported priority 1 (life threatening injury / illness) and 13 were transported priority 2 (not immediately life threatening). Air ambulances (AirLife), and the SAFD Ambus (mobile mass casualty transportation vehicle) were also both utilized to transport the multitude of patients we encountered. A search of the surrounding area was also conducted to attempt to locate any patients that may have attempted to flee the scene. An additional search will be conducted later this morning once the sun has risen. All questions relating to the potential criminal aspect of this should be directed to the San Antonio Police Department.

Police Chief William McManus says “This happens all the time,” and “This is not an isolated incident.”

Ten days earlier, Houston police officers discovered 12 illegal aliens locked inside a trailer in the sweltering heat of the Texas summer, Breitbart Texas reported. Officials stated the migrants told them they had been banging on the walls of the trucks for hours to get someone to release them.

Harris County District Attorney’s Office First Assistant Tom Berg said, “Thirty more minutes and this could have been a dozen homicide cases.”

Editor’s Note: This is a developing story and will be updated as new information becomes available. Initial reports indicated that two children were among the dead. Police officials later confirmed the children survived. This article has been updated to reflect that new information.

Bob Price serves as associate editor and senior political news contributor for Breitbart Texas. He is a founding member of the Breitbart Texas team. Follow him on Twitter @BobPriceBBTX and Facebook.