SAN ANTONIO (Reuters) - U.S. prosecutors are planning video depositions of witnesses ahead of the trial of a man charged with driving a truck packed with illegal immigrants in sweltering Texas heat, court documents showed on Wednesday. Ten people died.

Police officers work on a crime scene after eight people believed to be illegal immigrants being smuggled into the United States were found dead inside a sweltering 18-wheeler trailer parked behind a Walmart store in San Antonio, Texas. REUTERS/Ray Whitehouse

A pre-trial hearing for James Bradley Jr., 60, that had been scheduled for Thursday was postponed. Bradley waived his right to the hearing and to consideration of bail, according to the documents.

Bradley, who could face the death penalty, has told investigators that he was unaware of the human cargo until he took a rest stop in San Antonio on Sunday.

Prosecutors have said that Bradley knew what he was doing and acted with reckless disregard for human life.

Video depositions of people who were inside the truck are planned for Aug. 23 and will likely be the first time survivors tell a court what happened during the deadly incident.

Prosecutors said they have 13 material witnesses, and they are in federal custody. The U.S. Attorney’s Office for the Western District of Texas did not name the witnesses.

An attorney for the 13 said it was his understanding that they were on the truck.

“Since the government has taken the position that they are material witnesses, the government wants them to testify,” San Antonio attorney Michael McCrum said in comments sent by email.

The case brought new attention to the dangers of human trafficking as U.S. President Donald Trump’s administration pledges to crack down on illegal immigration.

Some survivors were seeking to offer testimony in exchange for consideration of visas that would allow them to stay in the United States, an attorney representing the Guatemalan Consulate in Houston said.

In a 2003 case of immigrant smuggling, considered to be the worst in U.S. history, authorities granted temporary visas to immigrants who provided testimony. Nineteen people died after traveling in an 18-wheeler truck through Victoria, Texas.

In the San Antonio case, at least 100 illegal immigrants, mainly from Mexico and Guatemala, were crammed into the back of the truck, investigators said.