people are down here taking care of it. how do you learn to drive in the dark like this? it s all instinct. these are the border patrol agents tom kaye says he relies on to keep him safe. there are almost 3,700 of them covering the 268 miles of buordr in tucson sector. we re with the border patrol that is in pursuit of two people that they ve spotted up on the mountain ridge in this area, and the reason we re shooting in night vision, we ve got to maintain a low profile. as we get out here to hike up into the mountains in pursuit. it s intense. i m pretty winded already. they re searching for the migrants up in the hills. they could be smugglers. they could be mules. we don t know. they could be armed.