RAFAH, Gaza Strip — When Fadel Shalouf’s family went to pick up his body at the morgue the day after he was executed on a busy Gaza street corner, they found his hands still cuffed behind his back. Hamas, the militant faction that rules Gaza, did not provide a van to carry the body to burial, so they laid him on two men’s laps in the back of a sedan.

It was an undignified end to a short, shrouded life. Mr. Shalouf, his family insisted, was an illiterate fisherman with a knack for designing kites when he was arrested at 19 by Gaza’s internal security service. Yet he was convicted in a Hamas court in January 2011 of providing Israel with information that led to the 2006 assassination of Abu Attaya, commander of the Popular Resistance Committees.

During last month’s intense eight-day battle with Israel, the military wing of the Hamas government brutally and publicly put an end to Mr. Shalouf, 24, and six other suspected collaborators. The vigilante-style killings by masked gunmen — with one body dragged through a Gaza City neighborhood by motorcycle and another left for crowds to gawk over in a traffic circle — highlighted the pathetic plight of collaborators, pawns preyed on by both sides in the long-running Israeli-Palestinian conflict.

“Fadel lived poor and died poor,” said his cousin Ahmed Shalouf, 28. “They left the bodies for a few hours in the streets, people spitting on them, throwing stones. They did not execute only Fadel. They executed all of us.”

For Israel, despite its advanced technology for tracking terrorists, human sources remain an essential intelligence tool that allows for pinpoint strikes like the one that felled Ahmed al-Jabari, operations commander of Hamas’s Al Qassam Brigades, at the start of the recent escalation. To Hamas, they are the enemy within, and vigorous prosecution as well as the occasional high-profile lynching are powerful psychological tools to enforce loyalty and squelch dissent.

Former intelligence officials and experts on the phenomenon said many collaborators are struggling souls who are blackmailed into service by an Israeli government with great leverage over their lives. Some are enlisted when they apply for permits to seek medical treatment in Israel, for example, or in exchange for better conditions or early release from Israeli jails. Others are threatened with having behavior shunned in their religious Islamic communities — alcohol use, perhaps, or adultery — exposed.

“There is no substitute to a human source, because a human source goes into their house, sometimes even into their minds,” said Yaakov Peri, a former head of the Shin Bet, Israel’s domestic intelligence agency. “With all the technology — drones, you name it — you need a background, and you need the assistance from a human source.”

Mr. Peri said Palestinian collaborators might be given money for expenses or a small salary, but “you’ll never be a rich guy.”

Hillel Cohen, a research fellow at the Truman Institute for the Advancement of Peace at the Hebrew University in Jerusalem, who has written two books on the subject, said some Gaza collaborators “do it just for some money” and “some to be part of a big story”; few are actually supportive of Israel, he said, but many have problems with Hamas.

“I interviewed a lot of collaborators, and they have a kind of inferiority complex,” Mr. Cohen explained. “They see the West, Israel, as much better than the Arab. I hear expressions like, ‘We’re worth nothing.’ Sometimes it comes from there, and sometimes it’s part of what the Israeli officers put in their minds.”

Collaboration has underpinned Israeli-Palestinian relations since before there was a modern state of Israel, dating back at least to the Jewish underground that operated during the British Mandate era in the 1930s. The Oslo Accords signed by Israeli and Palestinian negotiators in 1994 even made two villages — one in Gaza, one in the West Bank — safe refuges for about 1,500 Bedouins suspected of spying.

The very definition of collaboration has expanded in recent years. Some in Hamas and more militant groups consider the Palestinian Authority to be aiding the enemy when it coordinates security services in the West Bank with Israel. Since Hamas took control of Gaza in 2007 after winning elections, members of the rival Fatah faction who live here have almost universally been under suspicion. Selling land to Jews can be punishable by death.

But while experts on both sides estimated that 1,000 suspected collaborators were killed — mostly in summary justice — between 1987, the start of the first Palestinian intifada, and 1994, human rights groups have documented a relative handful of cases since. Of 106 death sentences imposed by the Palestinian Authority and Hamas-run courts since 1995, according to B’tselem, a leading Israeli human rights organization, 40 were for collaboration; through September, six of those collaborators had been executed.

Last month’s extrajudicial killings — all seven men had been tried and convicted, but several, including Mr. Shalouf, had appeals pending — were an echo of the public execution of at least a dozen collaborators who escaped from Hamas jails bombed during Israel’s last offensive in Gaza, the 2008-9 Operation Cast Lead. But they were a stark departure from Hamas’s efforts since then to pursue collaborators in court and not the street, spotlighting its dilemma as a movement rooted in militant resistance now trying to run a government.

The Qassam Brigades, Hamas’s military arm, claimed responsibility for the killings, but some party leaders condemned them. Issam Younis, director of Al Mezan Center for Human Rights in Gaza, said he met on Thursday with the Hamas justice minister and was convinced that the executions were being investigated and that their perpetrators would be punished.

“This is the challenge for Hamas: to what extent Hamas is closer to the mentality of a state rather than the mentality of the movement,” Mr. Younis said. “We’re talking about the law of the jungle. No one has the right to do such killing. The government has all the powers and legal institutions; they can do it properly on the basis of the law.”

The judicial process itself is fraught. According to B’tselem, 14 of the 40 collaborator cases since 1995 were tried in military courts, which human rights organizations consider inappropriate. All but three of the others were in state security court, including Mr. Shalouf’s, whose January 2011 conviction was based mainly on a confession that his lawyer said was coerced through torture.

In an interview four days after his death, Mr. Shalouf’s relatives said he had been abducted on Jan. 10, 2008, on his way to the sea in pursuit of sardines, sea bass and crabs. His father, Mussalam Shalouf, said he was summoned by the internal security service nine days later, and found Fadel, one of his 10 children, with broken fingers and burns from melted hoses having been dripped onto his skin, complaining that he had been hung from the ceiling by his ankles during interrogations.

Ahmed Shalouf, the cousin, said that far from aiding the enemy, Fadel had once helped the resistance by shuttling four fighters into Egyptian waters, violating Israel’s naval blockade on Gaza’s coast. He offered a photograph of Fadel on crutches around the time of the Abu Attaya killing as proof he was not involved.

“How can there be a collaborator who doesn’t have more than a SIM card? He can’t even write his name on the mobile,” Ahmed Shalouf said.

“If he was a collaborator, he would have built at least a room,” the cousin added, showing the former greenhouse strewed with debris where, he said, Fadel slept on a crude platform. “He would have bought a car. He would have bought clothes.”

Since Fadel’s imprisonment, family members said, neighbors have refused to meet their eyes. His younger brother, Bader, was arrested a year later on similar charges, but has not yet been tried. Mussalam Shalouf, 57, said that after Bader is released or executed, the family will leave Gaza, perhaps seeking asylum in Sweden.

“It’s like we are in a shed of cows, waiting their turn for slaughtering,” the elder Mr. Shalouf said. “After what happened with my sons, I hate all the people; I even hate myself.”

There was no mourning tent for Mr. Shalouf, no banners with his portrait, no music accompanying his passage to paradise. Instead, the men huddled in a hovel of corrugated tin and dark cloths, encircling a caldron filled with hot stones and ash they used to warm a kettle and light cigarettes.

Mr. Shalouf’s mother stayed in the house, five simple rooms off a concrete courtyard adorned with a poster of Yasir Arafat. She was the last to visit him in prison, four days before the airstrikes began raining down; next time, he had asked, bring peanut stew.

The men could not bear to tell her of the handcuffed execution in the streets, so they said the prison had been hit by an Israeli bomb. “Like he’s a martyr,” her husband explained.