As we look closer into the hot truck deaths, how is it that smugglers are able to sneak people passed all of the checkpoints?

On Interstate 35, about 30 miles north of the actual border with Mexico, is a Border Patrol checkpoint in Laredo.

It's one of the busiest commercial inspection stations in the country. It's also the last line of defense undocumented immigrants need to evade if they wish to continue their journey north.

Each commercial truck and passenger vehicles are funneled through inspection lanes where agents stop drivers and ask them a variety of immigration-related questions.

“Look at that truck traffic, it goes back about a mile or two,” Acting Deputy Chief Joel Martinez said.

Approximately 8,000 vehicles pass through this checkpoint every day, about 1.5 million a year.

Even with a number of agents, K9 dogs and technology, it’s not always enough.

“So we’re basically looking for needles in a hay stack,” Martinez said. “Just the sheer numbers alone, something’s bound to get through right? Unfortunately.”

It’s the same checkpoint truck driver James Bradley allegedly crossed. He was arrested in San Antonio Saturday after dozens of immigrants were found in his trailer.

Hiding in the back of the trailer is a dangerous chance that undocumented immigrants take.

“We’re starting to see more of an increase but apprehensions are down nationwide though,” Martinez said. “They are starting to hide them and taking bigger risks now.”

Martinez said it’s a daily phenomenon that’s been occurring for years now. On Sunday, agents found 12 people inside yet another hot trailer. A constant reminder to agents that they cannot let their guard down.

Agents at the checkpoint acknowledged that one of their commercial truck x-ray scanners they depend on to find abnormalities in the cargo was out of service. However there are other methods of detection they fall back on, they said.

No word yet on when the machine would be fixed.