More than 30 US senators have signed a letter demanding that the Trump administration open an independent investigation into the February killing of a 19-year-old American in the occupied West Bank, the ninth US citizen killed by Israeli soldiers or settlers since 2022.

The letter, led by Senator Chris Van Hollen of Maryland and addressed to the US secretary of state, Marco Rubio; the US attorney general, Pam Bondi; and the US ambassador to Israel, Mike Huckabee, asks for a US-led investigation and a full accounting of where all nine cases stand, and for the administration to brief Congress on the killing by 5 April. None of the cases have resulted in a criminal conviction.

“This has now become a consistent pattern in which Americans are being killed in the West Bank by settlers or the [Israel Defense Forces (IDF)] without justice or accountability, despite promises from US officials,” the lawmakers wrote in the Wednesday letter, which was shared exclusively with the Guardian.

Nasrallah Abu Siyam, born in Philadelphia, was shot on 18 February in the West Bank village of Mukhmas during an attack on Palestinian farmers by a group of masked settlers. Witnesses said that Israeli soldiers present did not intervene, provide medical assistance or make any arrests.

The IDF did not immediately respond to request for comment.

Thursday’s letter was signed by 31 Democratic and independent senators, including senior figures such as the senate appropriations vice-chair, Patty Murray; the Democratic whip, Dick Durbin; the ranking member of the Senate armed services committee, Jack Reed; and the Vermont senator Bernie Sanders. Notably absent are both of Pennsylvania’s senators, the Democrat John Fetterman and the Republican Dave McCormick, despite Abu Siyam being a Philadelphia native. Fetterman has been one of Israel’s most vocal supporters in the Senate over the last few years and has not commented publicly on the killing.

The state department confirmed the death of a US citizen in the West Bank on 18 February, and said it will “expect a full, thorough and transparent investigation” and sends “our deepest condolences to the family”.

“We condemn criminal violence by any party in the West Bank,” a department spokesperson said, “and take particular interest in this case due to our duty to protect American citizens”. The US embassy in Jerusalem has been in direct contact with the family, the spokesperson added.

The statement did not suggest the American government would be involved in the investigation, which senators demanded.

It is the second such letter Van Hollen has sent the Trump administration in less than eight months. In July 2025, he led nearly 30 colleagues in demanding answers over the killing of Sayfollah Musallet, a 20-year-old from Florida who was beaten to death by settlers. In that case, the state department said that it “calls for accountability in all cases where US citizens are harmed abroad”. Since then, two more Americans have been killed.

The nine dead span a range of ages and circumstances. Shireen Abu Akleh, the renowned Palestinian American journalist, was shot in the head by an Israeli soldier in 2022 while clearly identified as press. Aysenur Ezgi Eygi, 26, from Seattle, was also shot in the head during a West Bank protest in 2024. Omar Assad, an elderly Palestinian-American, died of a stress-induced heart attack after being gagged, blindfolded, bound and left on the ground by IDF soldiers. Khamis al-Ayyada, 40, died of smoke inhalation in August after a fire was set by Israeli settlers in his village. Three of the nine were minors: a 14-year-old from New Jersey and two 17-year-olds killed in separate incidents.

“For all nine of these killings, no one has yet been held accountable by the Netanyahu government,” the lawmakers wrote, “nor has the US government upheld its duty to protect Americans and secure justice and accountability for their deaths.”

Settler violence against Palestinians in the West Bank has increased sharply in the last two years. Dozens of villages have been emptied of their residents, with the support or even participation of Israeli government forces.

One of Trump’s first acts on returning to the White House last January was to revoke a Joe Biden-era executive order that had placed sanctions on settlers implicated in violence. Thirty-three individuals and organizations lost their designations overnight, which the senators say have caused the number of incidents of settler violence to subsequently shoot up.

“It is unclear to us how many more Americans must die in the West Bank in order for this administration, and other administrations, to take serious, credible steps to secure accountability,” the lawmakers wrote.

The department of justice, which would be involved in any US investigation, declined a request for comment.