GRANJENO, Texas (Border Report) — In what is the nation’s busiest sector in for migrant apprehensions, Border Report witnessed the arrests of 39 migrants ⁠— including several unaccompanied minors ⁠— during a ride-along with U.S. Border Patrol Agent Hermann Rivera on Wednesday in deep South Texas.

Starting before 6 a.m. near Mission, Texas, agents tracked seven adult men Rivera said had hidden in the brush. Helicopters operated by National Guard helped to pinpoint the area in the early morning darkness, using heat-seeking technology.

Shortly after that, another call came over the radio for “four bodies” they were searching for just a couple miles away. Again, helicopters, radio towers, and agents on the ground scoured the area for 30 minutes, and eventually concluded that the group “probably went back to Mexico,” Rivera said.

U.S. Border Patrol Agent Hermann Rivera (Sandra Sanchez/Border Report)

“That’s pretty common,” he explained, saying sometimes human traffickers will send multiple groups across to see which ones make it, and where agents are as they play a game of cat-and-mouse through the thick brush full of prickly pear, carrizo cane and thorny brush.

At 9 a.m., while driving slowly down a dirt road a half-mile from the Rio Grande near the small town of Granjeno, 30 migrants suddenly came out of the brush and turned themselves into Rivera. He sent the migrants walking up the road, where other border agents were already waiting. The migrants followed arrows the Border Patrol has placed in the area to lead migrants to safety.

“This was probably the best day of their lives,” Rivera said after finding them. Several of the migrants said they had been lost in the brush for three days and had not eaten or had anything to drink during that time. “They know when they see us, that they will be safe.”

Agents from Rio Grande Valley Sector of the U.S. Border Patrol currently makes about 300 arrests per day, down from 1,000 during the height of the migrant surge in the summer.