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James Bradley enters San Antonio's federal courthouse Monday morning,

James Matthew Bradley Jr. was charged for transporting undocumented immigrants in an unventilated, windowless semi truck — which resulted in the death of 10 men — Monday morning at San Antonio's federal courthouse. If convicted, the 60-year-old man could face the death penalty or life in prison.Bradley was arrested at a southeast side Walmart parking lot in the early hours of Sunday, after one of the men trapped in his cargo trailer escaped and told a Walmart employee about the 37 other people suffering from severe heat-related injuries inside. The employee called 911.When the San Antonio Police Department arrived, they found that eight of the passengers had died from the intense, triple-digit heat, and around 20 needed immediate medical care. Two more passengers have since died. Fire Chief Charles Hood said "a lot" of the passengers were likely to have irreversible brain damage from the heat exposure.According to the criminal complaint filed against him by Homeland Security agent James Lara, Bradley said he had no idea what kind of cargo he had been carrying. He'd been given orders from his boss to drive the tractor-trailer from Iowa to Brownsville, TX, where he was supposed to drop off the trailer to a person his boss had sold the vehicle to. Bradley said he made a stop in Laredo for truck detailing before driving to San Antonio (which is far off-course on a Laredo-to-Brownsville drive).Bradley said he only noticed something was unusual when he pulled over at a San Antonio Walmart to go to the bathroom — and heard banging from inside the trailer. When he opened the back door, the complaint reads "he was run over by 'Spanish' people and knocked to the ground." He could tell at least one of the passengers were dead, and many of them were lying in the truck bed "like meat." Instead of calling 911, he called his wife, but she didn't pick up.Passengers painted a different picture of their journey to Lara. One man who was transported to a hospital early Sunday morning told agents that he had been smuggled across the Rio Grande River into Laredo, Texas. After waiting in another hot cargo trailer for around 12 hours, the man was loaded into what sounds like Bradley's trailer. After the first hour on the road, he said, people began passing out from the heat — someone even made a small hole in the trailer wall where people "took turns breathing" from. When the driver finally stopped and opened up the rear door, there were six SUVs waiting in the parking lot. They were filled instantly by swarming passengers, and drove off.Walmart surveillance videos back up his testimony.Two other immigrants interviewed in the hospital Sunday said they, too, crossed into the U.S. through Laredo. One was headed to Minnesota, and said he believed there were up to 200 people in the cramped, hot trailer when he boarded. The other was instructed to pay a smuggler $5,500 once he got to San Antonio.At a Sunday evening vigil for the deceased immigrants hosted by RAICES, local immigrant advocates said they were disappointed in SAPD for immediately calling U.S. Immigration and Customs Enforcement after discovering the semi."RAICES condemns actions of SAPD who called ICE to respond instead of offering a humanitarian response," said Barbie Hurtado, RAICES' statewide organizer, at the event. "We resist all attacks to dehumanize the survivors of this tragedy. These immigrants lost their lives trying to seek refuge from violence, war and poverty. No human has to die in their search for a better life."Hurtado said the tragedy is a direct result of the criminalization of immigrants by the Trump Administration.Texas' top officials, however, have blamed the incident on Texas cities for embracing the so-called "sanctuary city" movement. In a Facebook post Sunday, Lieutenant Governor Dan Patrick said that welcoming undocumented immigrants into Texas "enables smugglers and cartels.""Sanctuary cities entice people to believe they can come to America and Texas and live outside the law," he wrote. "Today, these people paid a terrible price and demonstrate why we need a secure border and legal immigration reform so we can control who enters our country."This incident comes after months of SAPD Chief William McManus decrying the state's new law mandating law enforcement work more closely with ICE. Senate Bill 4, signed into law in May, ban cities from ignoring ICE requests to detain an undocumented immigrant until the feds can pick them up, regardless of the crime they committed. It's also been called Texas' "Show Me Your Papers Bill," for eroding local laws banning cops from asking anyone about their immigration status.In an i nterview with the Washington Post , SAPD spokesman Sgt. Jesse Salame said he expects the survivors of the trip will be handed over to ICE. "They have to be turned over to the custody of somebody," Salame said.