He was only 12 when he first stole into Israel from his home in a Palestinian farming village in the West Bank to find work. A few weeks later, he returned with more than $2,000 in wages.
Ever since, Ahmed has been working construction and agriculture jobs throughout Israel, from high-rise buildings around Tel Aviv to the melon fields on kibbutzes in the Negev desert. He has spent months at a time in Israel, some of it in hiding. To avoid arrest, he takes refuge in building sites, open fields or forests.
It hasn't always worked: Ahmed counts six stints in Israeli jails and a combined 2 ½ years of incarceration for working in Israel without a permit. If he's arrested again he risks additional jail time and thousands of dollars in fines.
But Ahmed and tens of thousands of undocumented Palestinian laborers like him continue to sneak into Israel anyway, going around, through and over the separation barrier of fencing and concrete slabs around the Israeli-occupied West Bank. The jobs he lands tend to pay about 200 shekels, or $57, a day.
The alternative, he says, is remaining in Palestinian areas of the West Bank where wages are one-third of those in Israel.
"Our lives are difficult. It doesn't matter if you sleep here in an unfinished building or in a field. Here, you can bring home bread and food for your kids," Ahmed, 27, said at his home in the village of Yatta. "Either you eat or you die."
Ahmed, who asked that his last name be withheld for fear of arrest, is one of more than 50,000 Palestinian laborers who work in Israel illegally on a daily basis, according to the Israeli state comptroller — despite the $4.2-billion separation barrier meant to seal off Palestinians in the West Bank from Israel's largest cities.
Started at the height of a Palestinian campaign of bombings and shootings in Israel about 15 years ago, the barrier has helped reduce attacks in the country, according to the government and security analysts.
But tens of thousands of Palestinian laborers for years have found ways to skirt the barrier.
Some scale sections of the 26-foot-high wall with ladders; others find drainage ditches underneath the concrete slabs to crawl across. The most common route into Israel runs through unfinished or damaged stretches of the barrier in the southern West Bank and near the city of Bethlehem farther to the north.
Although many Palestinians who are married with children successfully get permits for day work, Ahmed, who has a wife, an infant and a toddler to support, says he cannot because of his record of past illegal crossing offenses. He tries to take advantage of his good command of colloquial Hebrew despite being an illiterate elementary school dropout.
"We have nothing in the West Bank," he said. "Put yourself in my shoes: You have a wife and kids you have to earn money for. Where do you go?"
Among Israelis, workers such as Ahmed are known as shabachim, a Hebrew term for illegal resident.
For many Israelis, the workers are an irresistible source of cheap labor. An online search of shabachim brings up pages of legal advice aimed at employers, who risk criminal indictment, stop-work orders and fines.
Despite border police and army patrols of the West Bank frontier and police raids in Israeli cities, the thirst for Palestinian labor on farms and construction sites in Israel generates a labor flow that exceeds what Israel's security forces can handle. Even the threat of penalties for employers has not eliminated the challenge.
"Everybody knows what is going on and how many people work without permits — it's common knowledge," said Ala Khatib, the executive director of the Israeli worker rights nonprofit, Kav LaOved. "Most of them have never been a security threat, they are simple workers, mostly in agriculture and construction."
Ahmed's journey into Israel begins in his hometown of Yatta or nearby Dahariya. The villages are located a few minutes' drive from open stretches in the separation barrier where it is still possible to get across the frontier on foot.
Many Palestinians travel to the area from other parts of the West Bank to make the crossing. Sometimes they head out as the sun is setting so as to cross the border under the cover of the night. Other times they cross on weekend afternoons, when the presence of Israeli security forces is thin.
Laborers wait for a green light from Palestinian drivers and Israeli Arab smugglers on the other side of the barrier who watch the frontier to determine when it is safe to cross.
The laborers pay drivers about 250 shekels to cram into cars and vans that ferry as many people as they can fit. The drivers drop them off at locations a few feet from an unfinished section of the barrier near the Israeli settlement of Metsudat Yehudah. From there, it's often a frenzied sprint across the border into Israel, where a second driver waits to ferry the laborers to Beersheba or Tel Aviv.
"There's a saying in Yatta, 'Your legs are your life.' If you aren't in shape to run, you might end up in jail," Ahmed said from his home.
As the drivers traverse uneven mountain back roads, the laborers, their limbs going numb from being cramped, ponder whether they will get picked up by police.
"The worst time is when you cross," said Ahmed. "You're afraid you're going to go to jail. You are afraid there are dogs. You are afraid of the barbed wire."
A year ago, two Palestinians from Yatta who took a similar route around the fence eventually went to Tel Aviv, where they shot up a cafe in a popular tourist district. The attack killed four Israelis and renewed concerns about how easy it is for would-be attackers, as well as workers, to slip across the border.
Last month, a trio of West Bank residents who had skirted the barrier ambushed Israeli security forces near the Old City of Jerusalem, killing a policewoman.
Shaul Arieli, a former government advisor on peace negotiations and an expert on the West Bank barrier, said in an interview that most laborers go through a 6-mile hole in the barrier south of Jerusalem and a 25-mile gap in the southern West Bank.
"It's easy to cross the gaps in the barrier," he said.
Commanders for Israel's Security, a group of former Israeli security chiefs of which Arieli is a member, wants the government to close the remaining gaps in the West Bank fence and significantly expand the number of day permits allowing the entry of about 70,000 Palestinian workers.
The group says the government has hesitated to finish the barrier in part because Prime Minister Benjamin Netanyahu's right-wing government doesn't want to put what many consider a de facto border between Israel proper and Jewish settlements. The Defense Ministry declined to comment on the group's claim.
In recent months, Israel has started work to plug some of the gaps in the barrier with concrete walls, but a government comptroller's report cautioned that Israel has not allocated enough money.
Many people who cross into Israel illegally remain for weeks at a time to save on smuggler fees and to avoid being nabbed on the border.
After a day in late May of laying bricks at a municipal pool in the well-manicured middle-class Israeli suburb of Gedera, Ahmed showed a visitor his sleeping quarters: a neatly arranged pile of mattresses and blankets at the edge of a dirt field surrounded by the concrete shells of half-completed buildings.
Nearby was an unfinished villa where several laborers bunked. On the second floor, a Persian rug covered the dusty concrete floor as a place for the workers to sit and socialize after dark.
One of the workers stood guard to alert sleeping colleagues upstairs if the police should approach. The laborers said they often do odd jobs for Israeli residents nearby to buy their silence.
"The border police look in every building and in every corner," said Ahmed, as he watched an Israeli teen on a bicycle pass by. "Look at these happy kids who have everything. We didn't have anything. You know what it's like to stay here three months without going home, without seeing your own kids? It's a problem. There's no place to sleep."
"What can we do. If I had been a Jew, life would be good. I would travel. I would have a car. I would have money," he said. "But I came out Arab, a Palestinian, so it's worse."
Mitnick is a special correspondent.