Federal authorities will on Sunday begin to investigate a charter bus crash in far South Texas that killed eight people and injured 44 more in a single-vehicle rollover, officials said.

Seven people died at the scene Saturday morning on U.S. Highway 83, about 46 miles north of Laredo, and another died at a hospital, Texas Department of Public Safety Trooper Conrad Hein said.

“The driver of the bus lost control and rolled over,” he said. “Everything’s real preliminary right now.”

Hein said the driver was among the survivors. Hein did not release the identity of the driver or any passengers.

The trooper said it was raining Saturday morning but it was uncertain if that was a factor in the crash that occurred just before 11:30 a.m. He said no other vehicles were in the area at the time.

“Our troopers are going to look into what happened but it’s going to take us some time,” he said of the investigation. “We just know the driver lost control.”

The National Transportation Safety Board said it was sending a team to investigate the wreck starting Sunday morning.

Webb County Volunteer Fire Department Chief Ricardo Rangel told the Laredo Morning Times that the OGA Charters bus was heading to a casino in Eagle Pass, about 125 miles northwest of Laredo. The bus company is based in San Juan, in Hidalgo County in Texas’ Rio Grande Valley. A message left at the bus company Saturday was not immediately returned.

Hein said 23 people were taken to Doctors Hospital in Laredo, where the eighth victim died. Fifteen were taken to Laredo Medical Center. Seven were taken to a Dimmit County hospital in Carrizo Springs.

Priscilla Salinas, a spokeswoman for Laredo Medical Center, said bus passengers being treated there were in stable condition. She said she could share no additional information.

Laredo is about 150 miles southwest of San Antonio.

The crash is one of the deadliest bus accidents in Texas in recent years. In January 2015, two state corrections officers and eight inmates were killed near Odessa when a Texas Department of Criminal Justice bus tumbled 20 feet off a highway bridge and onto a Union Pacific freight train that happened to be passing beneath. The NTSB concluded Thursday that the wreck was caused by the bus hitting the guardrail.

In 2008. 17 passengers traveling to a religious retreat in Missouri died when a bus plunged over a highway bridge near Sherman. The NTSB blamed that crash on a retreaded tire on the right front axle that was punctured by an unknown object.

Although the retread itself wasn’t the cause, the panel noted that the tire was affixed to the front axle illegally, the bus company didn’t have the authority to leave Texas after failing an inspection three months earlier, and the company that inspected the bus wasn’t equipped to judge whether it was roadworthy. The owner of the Houston bus company was charged with making false statements but avoided prison in 2014 after a federal judge sentenced him to three years of probation in a plea agreement.

(AP)