LAREDO, Texas - About 30 miles south of the nearest border patrol checkpoint is an intersection of a popular truck stop and Interstate 35. It is places like this, that locals said undocumented immigrants and smugglers begin their journey.

A journey of hiding in tight spaces, sometimes unknowingly to truck drivers

Every time, before heading north, Diango Flores inspects his trailer truck. He opens the hood, takes a look under the motor, behind the cabin, and even inside the small compartments.

Flores said he doesn’t look for any mechanical issues, but people. Flores said someone could try to hide a child or a small person.

It's a necessary routine he said. After all, Flores uses I- 35 to transport goods from Mexico into the U.S. and sometimes all the way up to Canada.

Flores has been a truck driver for five years and said he's lucky no one has tried to use his truck to make it past the checkpoint. At least not to his knowledge.

He said he wouldn't like to lose his visa or his job, much less get arrested and be thrown in jail. That's why Flores tries not to spend too much time at the border.

"Laredo has thousands of tractor trailers that basically transport goods from the border to northern cities every day, every hour,” Laredo police investigator Joe Baeza said. “So a lot of the immigrants do hitch a ride unsuspectingly to those truck drivers."

Investigator Baeza said this is an ongoing trend.

Just last week, Border Patrol Agents discovered 33 undocumented immigrants inside a locked trailer. Many times the drivers are involved in human trafficking and resort to deadly measures in order to move people undetected.

It's a problem authorities on the border have dealt with for some time.

Investigator Baeza said they work with federal law enforcement to catch these trailers before it's too late. He said as long as there is money to be made and people living under the radar, human trafficking will continue to thrive.