Though he’d been in the U.S. Air Force for 22 years, Mohammed Abu Hashem felt like he had more to give. But that changed in October, when urgent messages poured in from family in Gaza.

An Israeli airstrike had killed Abu Hashem’s aunt and more than 20 neighbors, and left other relatives injured, he was told. Twelve children were among the dead, his family said. His thoughts turned to Washington’s “ironclad” support for Israel through policy and vast amounts of weaponry, and soon he concluded that 22 years was in fact enough.

“It was extremely emotional for me, knowing the amount of bombs that are being supplied to Israel was the cause of her death,” Abu Hashem, who is Palestinian American, said in an interview after retiring from the military in June. “I knew right then that I can’t be part of the system that enabled this.”

Abu Hashem, 41, said he was compelled to enlist after the 9/11 terrorist attacks on his adopted country. Today, he is among the smattering of experienced government officials and service members who have left their jobs disillusioned, they say, by the Biden administration’s management of the Gaza crisis and unflinching support for Israel in its campaign to destroy the militant group Hamas. His is the first known departure with such a direct connection to the war’s staggering civilian death toll. Others have sought conscientious objector status.

Saida Saleh Abu Hashem, Mohammed’s aunt, is at least the second Palestinian relative of an American service member to be killed in the Gaza war. This account is based on interviews with the former airman and people who know him, a review of messages he exchanged with Air Force superiors expressing alarm about the attack on his relatives’ home, text and voice messages shared by his family, and images of the damage to their apartment building in Gaza.

The Israel Defense Forces, which has faced allegations of using indiscriminate force throughout the conflict, told The Washington Post that its target that day was “a Hamas operational structure within a building” and that the operation involved two “precise” munitions. “The strike was planned,” a spokesperson said, to avoid excessive civilian deaths. The IDF declined to provide further details.

Abu Hashem cast doubt on that assertion. “If this is true,” he said, “and my family’s home was targeted by precise GPS-guided munitions, it wouldn’t be difficult for the Israeli military to release the evidence and the name of the Hamas operatives publicly.” It has not done so, he noted, or demonstrated that the strike was “imperative.” Humanitarian groups have said Israel’s tolerance for civilian deaths when striking militant targets is far too high.

Abu Hashem said he spoke to Air Force superiors about his concern that Israel, Washington’s closest ally in the Middle East, had potentially committed a human rights violation, and may have used U.S.-supplied weapons in doing so. He called their response unsatisfying, and said it was a factor in his decision to end his government service.

“I can’t serve an administration that disregards facts,” he said, “and denies U.S. and international law to defend and enable such horrific violence.”

An Air Force official, speaking on the condition of anonymity to describe Abu Hashem’s interaction with his superiors, defended their handling of the situation and characterized their response as “empathetic.” This official said an enlisted leader who joined Abu Hashem’s unit in December offered him assistance, as did a predecessor, but acknowledged that they were at a loss over what to do.

“They behaved in a manner I would have expected,” the Air Force official said. “ … As you know though, no one in the Air Force has the ability to change foreign policy decisions.”

Both sets of Abu Hashem’s grandparents were farmers in Yibna, a village outside Tel Aviv. In 1948, he said, they were forced to flee when Israeli soldiers seized the territory, among more than 700,000 Palestinians who were driven from their land that year after Israel declared independence and the first of several Arab-Israeli wars ensued. The family reached Gaza, where his father, Saady, was born in a refugee camp.

As an adult, Saady Abu Hashem fled to Qatar, where Mohammed and five of his six siblings were born. Mohammed recalled, as a 4-year-old, meeting his extended family in Gaza and touching their hands through the Egyptian border fence.

In 1991, when he was 8, Abu Hashem’s parents moved their immediate family to the United States, eventually settling in Ohio where his father started a successful jewelry store.

Abu Hashem said he joined the Air Force because he “felt that sense to protect my family.” He worked on KC-135 refueling aircraft, a job that deployed him ten times, including three mobilizations to Qatar, where he was able to connect with other family uprooted from Gaza.

As he climbed the ranks, Abu Hashem switched careers and became a first sergeant, a leadership position responsible for advising commanders on training and quality-of-life issues. He said he relished the role, working for several units before arriving at Joint Base Andrews in Maryland in April 2023.

On Oct. 10, Mohammed’s aunt, Saida Saleh Abu Hashem was home in northern Gaza’s Jabalya neighborhood with her husband and two of her three sons. At least two other families shared their apartment building, including children.

It was three days after Hamas militants led the stunning cross-border attack into Israel in which they killed 1,200 people and took about 250 hostages. Israeli forces fired a warning shot at a building two doors down the street that was loud enough for most in the neighborhood to hear, Mohammed Abu Hashem said. The practice, known as “roof knocking,” involves munitions with little or no explosives. Though largely abandoned now, it was intended to signal to civilians that a strike was imminent.

What happened next was described in voice messages sent to Abu Hashem by his aunt’s other son, whose name also is Mohammed. He was attending school in Turkey when his mother was killed.

Hearing the warning shot, families evacuated, but nothing happened. After waiting outside for about 90 minutes, they returned to the home. Saida Saleh Abu Hashem was in her living room when the bomb struck. She was 49.

“Suddenly, stones were falling on them,” Abu Hashem’s cousin said in the recording, surmising the Israelis had waited for everyone to go back inside and then “demolished the entire house.”

In all, 23 people died as a result of the strike, Abu Hashem’s cousin tallied. Among them was a family of six who lived in the same apartment building, according to a death registry maintained by the Gaza Health Ministry. The youngest was a 1-year-old girl.

“I know everyone there, and all of them, without exception, are civilians working in civilian jobs, including teachers, car drivers and a supermarket seller,” Abu Hashem’s cousin said in the recording. “I am certain that there are no resistance fighters or armed elements in this building.”

In its response to The Post, the IDF did not address questions about whether commanders assessed civilians were harmed in the attack or if they are confident the correct building was hit. Israeli and U.S. officials have said Hamas militants hide among civilians, though the two sides have had sharp disagreements about Israel’s efforts to limit civilian casualties.

The home was probably struck by U.S.-made MK82s, guided 500-pound bombs, or similar Israeli weapons, said Trevor Ball, a former U.S. Army bomb technician who reviewed photos and videos of the strike’s aftermath at The Post’s request. The MK82 is one of several American munitions that has been provided to Israel. The imagery, captured by neighbors and bystanders, does not include any identifiable munition components or fragments.

Abu Hashem said he sought to channel his grief into something productive. He confided in a friend, a senior enlisted leader in the Air Force, that he was struggling but hopeful that providing information about the strike on his family’s home would lead to the discovery of a war crime or reveal to the Israelis that a tragic accident had occurred. His friend, he said, told him she would pass along the details to contacts in the intelligence community.

Nothing came of it, Abu Hashem said. His friend, who has since left the service, did not return a request for comment.

Frustrated by the inaction, Abu Hashem decided in late October that it was time to go.

He took a temporary position at a company in the Akron, Ohio, area through a program for service members transitioning to civilian careers. In February, he was introduced to a younger man also leaving the Air Force. They exchanged pleasantries, but Abu Hashem made no mention of why he had left the military.

Days later that airman, Aaron Bushnell, doused himself in gasoline and lit himself on fire in front of the Israeli Embassy in Washington. “Free Palestine” were among his last words. Greg Kennedy, who oversaw Abu Hashem’s work at the company, Leaf Home, confirmed the two men’s brief encounter.

Abu Hashem said he wonders what, if anything, he could have done to steer Bushnell toward another path, but that his grief was too overwhelming to share. “I had an opportunity to talk to this young man about my life,” he said. “I chose silence.”

Abu Hashem said his relatives in Gaza face an uncertain fate. They’ve been relocated to a camp for the displaced in Rafah, the city in southern Gaza where Israel began an offensive weeks ago that has forced more than 1 million people to flee. His uncle, in a voice message, spoke of the tents baking in the summer heat, hepatitis infections, and starving people grinding corn and animal feed as a last resort.

Abu Hashem criticized the Israeli military for not disclosing “any evidence to back up the reasoning for the strike” on their home. There are “no checks and balances to their narrative,” he said.

“What we should really be asking here,” he said, “is why my aunt’s life and the lives of innocent children were considered so worthless that they could just be considered collateral damage.”

Hazem Balousha in Cairo, Hajar Harb in London, Reem Akkad and Meg Kelly contributed to this report.