I live an hour south of Del Rio, on the border.
Going into Mexico is easy. No passports needed, no searches, no need to “know people”. You pay the bridge fee and go on over. All the security at the bridges on the US side is for people coming BACK into the US.
There are also various Border Patrol checkpoints on the main highways coming to the border (hwy 90, 57, 277). They don’t stop and check people coming towards the border, but they are equipped with cameras, capturing all the traffic going through. However, there are backroads to get around these checkpoints if you know the area.
There are also a couple alternate routes to Del Rio from the Corpus area. These side routes are sparsely populated, not heavily patrolled, and mostly frequented by oil field workers. If they took one of these off-the-beaten-path routes, these criminals probably drove right by my house