(NewsNation) — So-called “brush teams” help patrol the nation’s southern border, and they’re popping up in the U.S.  

The local law enforcement teams scour the stretch of land where migrants sometimes hide and run. If all is aligned right, brush teams are in the right place at the right time, catching those on the run.

NewsNation’s Ali Bradley embedded herself with brush teams across the southern border to see law enforcement’s efforts to capture migrants who enter the United States without authorization.

People come fleeing other countries, many avoiding the U.S. legal border crossings. Sometimes, they receive help from cartels.

“Are they part of a gang?” asked Sgt. Tal. Parker with Special Operations SABRE. “Are they coming here to do something else? “

According to Customs and Border Protection, an estimated 75 criminals on the Terror Watchlist have come across the border without authorization so far in 2024.

That fact fuels local law enforcement to play a dangerous game of cat and mouse.

Day and night, U.S. law enforcement patrols and tries to capture people entering the U.S. outside of authorized checkpoints.

Choppers and drones assist overhead using infrared thermal imaging.

They work alongside Border Patrol agents when those agents aren’t pulled away to help with the record-breaking numbers of migrants at authorized crossing ports. 

From January to March this year, 308,000 migrants passed through border facilities.

NewsNation’s Ali Bradley caught up with a brush team in the southeast corner of Cochise County, Arizona, where the cartel has carved a path through a national forest.

Officers ran across difficult terrain in total darkness, often capturing six to 10 people who had crossed the border and run for cover. Sometimes, they follow the cartel’s path to a stash of camouflage clothes, waiting to conceal them until a vehicle picks them up — that is, unless a brush team beats them to it. 

Cartels use many migrants as drug mules, finding creative ways to push pills — and other drugs that fuel their billion-dollar empire — across into the U.S.

So far this year, a total of 24,000 pounds of drugs are seized at the southern border on average every month.

The brush teams are catching the migrants coming to the U.S. on foot, but human smuggling can take different forms.

One group was smuggled by boat, landing on a San Diego beach to awaiting cars.

Another group of four migrants was concealed inside a dresser, and countless others were often packed inside vehicles.

NewsNation was there when police pulled over the driver of a Volvo. The driver told officers he was a photographer on his way to take pictures.

Officers suspected otherwise.

“This dude is sweating bullets, and he’s got the back partition covering the rear of the vehicle. There might be something,” Cochise County Sheriff’s Office deputy AJ Shaw said.

Their suspicions were right. There were two people concealed in the back.

“We just talked with Rosia. She was in this vehicle … threats from the cartel, didn’t pay, but running away,” an officer said.