On August 9, the Saudi-led coalition waging war on Yemen carried out a horrific attack on a school bus, killing dozens of people, including 40 children.

When I asked the Pentagon if the United States — which supports the coalition’s effort by refueling its warplanes, providing intelligence help, and selling them explosives — made the bomb used in that attack, the answer was less than reassuring.

“We may never know if the munition [used] was one that the US sold to them,” Army Maj. Josh Jacques, a spokesperson for US Central Command, told me. “We don’t have a lot of people on the ground.”

The military could conduct an investigation to find out if that’s the case, but it’s unclear if that probe would ever happen or how long it would take, he continued.

Well, it turns out CNN launched an investigation of its own and reported last Friday that the bomb used in the attack did, in fact, come from the United States.

Per the report, the 500-pound, laser-guided explosive was made by Lockheed Martin, one of America’s largest defense companies that sells weapons to militaries around the world, including Saudi Arabia’s. The State Department approved the sale.

Navy Lt. Cmdr. Rebecca Rebarich, a Pentagon spokesperson, told me on Monday that the Defense Department “cannot independently verify what may have been found on site” and referred me to speak with Saudi officials.

But, she noted, “the US is not investigating strikes conducted by the Saudi-led coalition,” adding that the Defense Department takes “all credible reports of civilian casualties seriously.”

That’s somewhat surprising, as the strike in Sa’ada that killed innocent civilians is not an isolated incident. A CNN graphic captured by journalist Tim Shorrock on Twitter shows that the Saudi-led coalition previously used US-made bombs from different contractors to kill hundreds of people.

Astonishing graphic from @CNN, identifying civilian massacres in Yemen with the bomb makers - Raytheon, Lockheed Martin and General Dynamics. This should be standard in war reporting. Searing images. https://t.co/EZqkSsAri6 pic.twitter.com/NWJvPuN7ct — Tim Shorrock (@TimothyS) August 18, 2018

To summarize: The Saudi-led coalition is using American-made weapons dropped from planes refueled by Americans to kill civilians — including children — and the Pentagon won’t look into it.

As Rebarich explained it to me, the Pentagon doesn’t “provide or vet the Saudi-led coalition targets.”

The US says it wants an investigation, but America won’t lead it

On August 12, Secretary of Defense Jim Mattis said he sent a three-star general, Army Lt. Gen. Michael Garrett, to encourage the Saudis to investigate what happened in the Sa’ada attack. According to the Defense Department, Garrett has already pressed Saudi Arabia to conduct a “timely and transparent investigation.”

That’s unlikely, though, as a top spokesperson for the Saudi-led coalition defended the August 9 strike by calling it a “legitimate military action.”

In the meantime, the US continues its three-year support for the Saudi-led coalition’s war in Yemen. The coalition, which includes other US allies like the United Arab Emirates, is fighting an Iran-backed rebel group called the Houthis, who staged a coup in 2014 to take over Yemen’s government.

The war has claimed more than 13,500 lives, with more than 900,000 suffering from cholera. Roughly 20 million Yemenis need humanitarian assistance to meet basic needs — including food and water — out of a prewar population of 28 million. These are all just estimates, though, as conditions on the ground are so bad that no one can do an official count. What’s worse, the US is helping make those conditions as bad as they are.

The Sa’ada attack, and the images of dead and bloodied children that came out of it, has led to an upswell in calls for America to end its involvement in the conflict.

On Saturday, the Washington Post’s editorial board said the US is perhaps “complicit in a probable war crime.” And on Monday, Sen. Chris Murphy (D-CT), a longtime critic of US support for the Saudi-led coalition in Yemen, said he’ll propose an amendment to cut off funding for America’s support for the war.

It’s unclear, as of now, if it will receive the necessary votes in Congress, as similar efforts have failed before. It’s therefore entirely likely that the current pushback will amount to nothing — except continued US backing for one of the most brutal wars in recent memory.