Inside the sale barn, old metal cinema seats have been racked up on three sides and the giant propeller fan fixed to them is so efficient that it almost blasts the hair off the skulls of people sitting closest to it. There’s a children’s auction in progress. A wide-eyed, gawky girl leads her sheep around the sawdust ring. ‘These are all ranchers’ kids,’ Chavez explains. ‘They raise these animals themselves. Money goes to charity, in case you’re tempted into buying anything.’ The gawky girl goes to sit down in the stalls. She watches her sheep, knobble-kneed in the ring, and crosses her fingers behind her back. The auctioneer calls the auction as if he’s speaking double Dutch on fast forward. Emmy giggles. Jack imitates him in a Disney voice: ‘Gobbledee, gobbledee, gobbledee.’ ‘Hyperbole, hyperbole, hyperbole,’ the auctioneer reciprocates, and in the choked dustiness of the tent I find myself searching faces for Duval. Where was he? What really happened out there in the desert? That Duval was responsible for locking the coyotes in the truck, I had no doubt. But that he had intended them to die? I don’t know; and if not, how could he have been so certain the Border Patrol would release them in time? Questions spin around my head. How many men had Duval killed? Was he any better than a vigilante himself? Then I began to picture it. The blackness in the truck. The fearful heat. Seventeen people with nothing left to them but to measure the pounding of their hearts as the temperature kept on rising. Had they waited quietly, conserving oxygen? Or had they struggled, panicked, tried to beat that door open? Seventeen human beings. Two old men, and women, amongst them, and I think I would have locked the coyotes in that truck had it been Emmy or Jack. And hadn’t this been how Estella’s journey began?

Duval told me he came to the border to learn the truth, but he’d found more than that. There were two truths: what had happened to Estella and her son, and the reality of what was happening every day. Despite everything, he had fallen in love with the border. For its beauty and its ugliness, for its passion and all its secrets. And in his more philosophical moments he persuaded himself that in staying he’d found some measure of purpose.

‘Helping people or looking for this El Turrón character?’ I’d asked him. ‘Looking for revenge?’

‘You don’t think revenge is a good enough reason?’

I’d thought then of all the reasons people give to justify decisions that ultimately trap them. Security, money, children, fear, and I decided that revenge was as valid a rationale as any.