DALLAS (CBSDFW.COM) – In a desperate bid for a better future, authorities in San Antonio made a deadly discovery in what they call a “horrific” case of human trafficking.

Authorities say at least nine people died after they were crammed into a tractor-trailer during the middle of the summer heat in Texas. The tractor-trailer was found outside a Walmart in San Antonio late Saturday and into early Sunday. Authorities are calling this an immigrant-smuggling attempt gone wrong.

“They put their lives on the line, but don’t understand the perilous journey that takes place that they’ll have to endure to get to the U.S.,” said Keith Owens, a retired special agent for Homeland Security.

Owens has been in law enforcement for over 20 years, and he says there’s one thing that fuels human trafficking and smuggling – greed. “These people are here for a quick buck. To be paid,” he said.

He says smugglers look for different areas like truck stops and bus stations to move people.

Lindsey Speed works with human trafficking victims and says human smuggling is happening in Dallas/Fort Worth.

“Most of the time, it’s from another country, so they’re coming through DFW… since we’re not a border city, per se… I think a lot of it may be coming through our city since we’re a big transport city,” said Speed.

Speed urges people to trust their gut when it comes to helping to spot victims.

“We’ll see things that are weird, and sometimes you don’t know that you know… but something’s not quite right. Make the call. Do the report. And ask questions,” said Speed.

Questions like “Do you know what city you’re in?” and “Do you need help?” leads to a simple conversation that could help save lives.