An Israeli investigation has revealed a 23-year old Palestinian woman and her 16-year old brother were killed last week at an army checkpoint in Jerusalem by civilian security contractors, not soldiers.

The siblings who were killed, Mariam Abu Ismail and Ibrahim Taha, were en route to Jerusalem on April 27th, having received their first permit to enter Israel from the West Bank. Abu Isamil was supposed to have medical treatment in Jerusalem. Unfamiliar with the procedures of Qalandia checkpoint, the main military artery into Israel, the two wandered into a vehicle lane where pedestrian traffic is prohibited.

According to a police inquiry, Abu Ismail and Taha were told to leave the vehicle pathway. Abu Ismail then thew a knife at officers. A soldier discharged warning shots, but a private contractor fired rounds into the two Palestinians killing them. Witnesses said they heard seven shots.

Contractors are allowed to use force, but unlike soldiers who are monitored by army investigators, there is no automatic internal review mechanism for security companies. The Israeli Ministry of Defense has said it will conduct a probe at a later date.

The shooter, whose identity was not disclosed, is likely employed by the $180 million Israeli security conglomerate Modi’in Ezrachi.

Modi’in Ezrachi has personnel working in eight checkpoints in the West Bank including Qalandia, according to a report published in January by the Israeli human rights group Who Profits. The security company provides civilian security to government agencies, settlements—including 11 illegal outposts—and at the Western Wall plaza. Job listings from the group target veterans or persons with marksman skills, although “no experience necessary.”

The company’s website says its workers guarding checkpoints “balance between security needs and the needs of those residing in the State of Israel and the Palestinian Authority,” continuing, “and does so with great success.”

In 2010 a Modi’in Ezrachi guard killed a Palestinian from East Jerusalem. The contractor was never criminally charged. The Association for Civil Rights in Israel then filed a petition in the high court to remove private contractors, citing their lack of transparency and accountability.

“The private guards’ norms of conduct are vague and unknown to the local population,” said the group. “It is unclear who is in charge of receiving complaints against them and what measures can be taken, and although the law requires security guards to wear name tags to guarantee accountability, this requirement is overlooked.”

The case was lost, and failed to gain traction within Israeli society on the use of private security.

Privatized checkpoints first appeared in 2006, after the Israel’s parliament voted for contractors to control or support 35 of the 96 checkpoints in the West Bank. The decision to add private-sector operatives was made in the context of a general build-up of checkpoints following the second Intifada as a means to streamline and manage the increased forces.

Who Profits found budget constraints prevented a full exchange of forces. Companies are awarded more than $200 million per year to provide civilian security forces.

Today contractors are posted at 12 checkpoints in the West Bank in conjunction with the Israeli military, and inside dozens of settlements. Who Profits reported they amount to 135,000 private guards, of whom 50,000 carry fire arms.

Initially Israel hoped the civilian guards would smooth uneasy encounters.

“The idea is to make the checkpoints civilian,” Ministry of Defense spokesperson Shlomo Dror told the Financial Times during the first phase of the rollout.

“The Palestinians will meet civilians not soldiers. Nobody likes security checks. But what we are trying to do is to make it easier on the one side and, on the other side, not to skip security needs.”

Yet private contractors brought with them stricter regulations. They had written out guidelines for searches while at the time the military did not, wrote Who Profits.

When stationed at checkpoints contractors are hired on as inspectors, tasked with interfacing more closely with Palestinians than the Israeli military or border police. The civilian agents do not wear identifying badges and often dress in uniforms that do not include a company insignia.

Despite a wide swap out of soldiers for forces for-hire, many Palestinians are unaware private security contractors work at Qalandia checkpoint.

“Most of the people who go through the checkpoints cannot distinguish between these two groups,” Who Profits said. Although there is a popular line of questioning raised by private contractors and not the military: food.

Who Profits noted contractors are unbending on the prohibition. “The regulations are very strict and they deal with every small detail such as the amount of food a Palestinian working in Israel is allowed to bring with him. The arbitrary allotment prohibits, for example, bringing in big bottles of water and oil or cooked meals.”

A second private Israeli company, Sheleg Lavan, operates in a further seven checkpoints in the West Bank.

Aside from inspectors, security contractors support checkpoints with high-tech systems of identifications. In addition to presenting their identification cards, at Qalandia Palestinians workers with permits to enter Israel must undergo fingerprinting and facial recognition tests. The software is sold to Israel’s Ministry of Defense by the American company Hewitt-Packard. Who Profits said the technology was developed with a subsidy from the U.S. government, a line-item in the Wye River Memorandum, or the 1998 round of Israeli-Palestinian peace talks.

Another contractor, G4S Israel, sells machines for full body scans conducted at checkpoints. The company is an Israeli-owned subsidiary of the British-Danish group known for operating private prisons, Group4Securior(G4S).