Last fiscal year, Customs and Border Protection seized 27,000 pounds of fentanyl nationwide. Nearly half of that was seized in Southern Arizona.

One of the departments layers of security is its K9 team that sniffs out smugglers, which the agency calls the largest law enforcement K9 program in the country.

CBPs K9 units work at ports of entry along the U.S.-Mexico border and at checkpoints like the one on I-19 near Tubac. They even work in the desert to track down people trying to get around Border Patrol checkpoints.

Last fall, a K9 sniffed out four abandoned duffel bags in the brush, filled with a more than 70 pounds of meth and 60 pounds of fentanyl. The combined street value was estimated at nearly half a million dollars.

Any amount of fentanyl we can get, keep off the streets, is very significant, Border Patrol agent Martin Whelan told KGUN. He has worked as a K9 handler and knows the intense training it takes to become one.

The K9 will be at the academy for a couple of weeks prior to the handler arriving, he explained. And then its two months where the handler and the K9 work hand-in-hand in training We have to show that we can read the K9s behaviors and get certified. And then we train bi-weekly with our K9s to maintain our certification.

CBP runs a breeding program for its K9s. They start their training to find hidden people and drugs as young as seven-month-old puppies.

The most common breeds well have are gonna be German shepherds, Malinois, Dutch shepherds, said Whelan. And theyre selected for their prey drive and their willingness to work. Its a tough environment for a K9 to work The sun out here is very taxing on a K9.

But CBP says these patrols and checkpoints are critical to stop smugglers who cross illegally, or make it through ports of entry.

Just this week at the I-19 checkpoint, a Border Patrol K9 alerted agents who found 16 migrants locked inside a refrigerated tractor trailer set at just 50 degrees. The driver, a U.S. citizen, faces criminal charges.