Who is sneaking fentanyl across the southern border? Hint: it's not the migrants

We know that illicit fentanyl is flowing into the U.S. from Mexico. Yet we rarely hear from the couriers who smuggle most of it through legal ports of entry. This is one of their stories.

Just before midnight on Aug. 4, 2021, Haley tried to cross the border from Mexico back into Arizona, where she lived. She was carrying 1,000 fentanyl pills inside her body.

"That was the first time I've ever done it," Haley says. "It was just a sudden decision that I made at the last moment."

At...