BAD LANDS

Badlands
You were already told what to do in the cutscene, so you need to head up the mountain, kill the witness and bring back proof, in photographic form. Jump on the Sanchez and make your way up the side of the mountain. Start at the red circle at the bottom, then make your way around to the left and eventually you'll come to a small forest. In the middle of the trees is a cabin, and that's there the witness can be found. When you get too close the FBI will start shooting at you, but don't worry about it, soon enough a cutscene will start and the witness will try to get away. Chase after him and follow him off the mountain. Even if you have no guns, he'll bail from his car at the bottom of the mountain. Chase after him and beat him to death. Once he's dead use the camera and take a photo. After you've got it, drive to the drop off point and deposit the camera.

Mission Passed!

After the mission you'll receive a phone call from Cesar telling you he sent his cousin over to help you out, this will open up a new mission on the radar. Head to the question mark for a new mission. You'll also receive a phone call from Sweet saying prison is fucked up and he wants to be out soon.