EDINBURG, Texas -- Just outside McAllen, Texas, Border Patrol agents invited CBS News on an immigration bust. Earlier in the day, officials stopped a smuggler, and after interviewing four immigrants, they were able to identify a house with about 40 people inside.

"Quite often what will happen is somebody may have a cellphone and because the conditions are so bad they will call 911, and that's how we are able to uncover some of these 'stash houses,'" said Deputy Chief Raul Ortiz.

In the kitchen, it was clear food was being made, and there were flies all over the place.

One immigrant inside was Elma Galindo Alvarez, who says she paid $8,000 to a smuggler to get there. She had been there for the last 15 days. But it's not her first time coming into the U.S. illegally. She told us she's tried to come over once before.

Border Patrol says the people in that home are the same kind of people who get packed into tractor trailers or SUVs and are driven around border checkpoints. When Border Patrol arrested the smuggler who tipped them off to the house, he gave them the garage door opener and told them exactly what they would find.