When Gilbert set out to escape the misery of life in Zimbabwe by sneaking across the border to South Africa, he thought he knew the risks.
By Orla Guerin
BBC News, South Africa's border with Zimbabwe
He expected to face hunger, thirst and exhaustion, and perhaps the South African army and police.
He did not expect to be hunted down by a group of white South African farmers. But he found himself in the back of their pick-up truck, hands bound with cable ties.
It was late in the afternoon and Gilbert was hot and hungry. He told us he was 45, but he looked older.
"I feel so tired and so weak," he said in a voice that had shrunk to a whisper.
"We are hungry in Zimbabwe. There's no food and no jobs. We are really suffering."
He had been deported the day before, but had already sneaked back in. He told us he would try again, after a few days' rest.
If and when he does, the farmers will be waiting.
They are private citizens, and some of them are armed. They are well-organised and well-equipped, with walkie-talkies and flashing lights on their trucks.
An estimated 3,000 Zimbabweans cross daily into South Africa
They dress mostly in khaki and call themselves the "green-light police". They admit that others may call them vigilantes.
The farmers organise patrols that go deep into the bush more than 50km (30 miles) from the border, rounding up anyone who appears to have crossed the border illegally.
They maintain that the Zimbabweans cut their fences and threaten their livelihood, and say that some commit violent crime.
Along a railway track they caught sight of a few distant figures, running for cover.
Some could not run fast enough. Within minutes a man was loaded on the pick-up, protesting all the way.
He insisted he had not come from Zimbabwe, but he could not prove it.
He begged not to have his hands tied: "I'll never run again. I'm sick. I'm not guilty."
But his pleas were ignored and his wrists were bound.
Soon he was joined by a 25-year-old called Nyashadzashe, who said he had fled the meltdown in his homeland for the second time.
He did not know the men detaining him were farmers. He thought they were "hunters on safari".
His story is a familiar one.
"I came using feet," he said. "It's almost three days now. No food, no water. I'm exhausted. My heart is not feeling well."
Nyashadzashe's journey across the border had cost him dearly.
He had sold his last two goats to finance the trip, hoping that in South Africa he could earn money for his ageing parents, two wives and young son.
But he was robbed of his last penny en route.
He told us he would try again, because otherwise he would starve.
"In Zimbabwe there is nothing," he said.
One of the farmers, Willem Helm, stood at the back of the pick-up, listening to his account.
He said he felt sorry for the Zimbabweans and would do the same in their shoes, but the patrols would go on.
"We don't beat these people up," Mr Helm said.
"We don't chase them. If they run away and we can't catch them we let them go.
"We had to do something. Otherwise I must pack up and go. Where will I go?"
'Face of fear'
The farmers say they catch 10 to 15 men every time they go out.
Once they have filled their pick-ups, they summon the local police who collect the Zimbabweans for deportation.
But the local police chief wants the farmers to stick to farming and stop taking the law into their own hands.
Calvin Sengani, the Limpopo Province Police Commissioner, says they would be doing him a favour if they arrested people for committing crimes, but not just for crossing the border.
"They are impairing people's rights when they tie them. That is committing assault," he said.
I asked if he would be taking any action.
"If anybody complains that they have been tied for doing nothing, then we will charge the person who did that," he said.
But weary and frightened Zimbabweans who have crossed the border illegally are not likely to be making too many complaints.
No one knows for certain how many so-called "border jumpers" make it through every day, but the latest estimate is 3,000.
Even in broad daylight you can see men and women squeezing under the razor-wire border fences, or clambering over the top, sometimes with infants in their arms.
More than 100,000 people were deported to Zimbabwe in the first six months of the year, but for many the frontier with South Africa has become a revolving door.
Zimbabwean refugees are now part of the landscape in the border region.
"You always know them the minute you see them," one local man said. "Their faces are full of fear, and they are ready to run."