This is the Netse Yehuda Battalion, an israeli army unit showcasing their military might in a promotional training video. But the unit has a decades long history of abusing Palestinians in the West bank, and the Americans know it. A State Department investigation found they had committed gross human rights violations, but this finding never led to us sanctions. Even media reports of possible sanctions outraged Israel. So despite their track record, the Netzer Yehuda battalion is still receiving american arms and is now operating in Gaza. We tracked down one former soldier from the unit. In a rare interview, he remembers fellow soldiers bragging about their excessive violence towards Palestinians. We've hidden his identity and voice as he fears reprisal.

There were some kids throwing rocks in a small village that normally isn't a big deal. But the company commander decided, let's throw them a party. So they took the emergency response team and 20 soldiers. They walked door to door throwing flashbangs and gas grenades into people's homes as a punishment for the kids throwing rocks.

Collective punishment?

Yes, collective punishment, the commander said. It was fantastic to see the look on their faces when we look at.

Those abuses that have happened in Netse Yahuda over the years. There's a chain of command here. What responsibility does the battalion commander, the person at the very top, what responsibility does that commander have for what happened?

I think he has all the responsibility. If these commanders dont put their foot down and punish them for their behavior, then they are in fact condoning their behavior.

He told us his years in the battalion changed his outlook completely. He now feels compelled to speak out about the battalion's mistreatment of Palestinians. The officers he's talking about follow a chain of command. What happens under their watch is their responsibility. But despite this, we found some of these same commanders who were in charge when allegations of human rights abuses emerged have been promoted again and again into senior roles in the IDF using facial recognition technology. CNN found this commander, Lieutenant Colonel Nitai Okashi, now in Gaza, in a senior role running ground operations back in 2019. He ran the Netse Yehuda battalion and was in charge when these soldiers seen here laughing as they beat and humiliate a palestinian man and his son, both arrested for assisting the killer of two fellow Netsa Yehuda soldiers. Their journey to the police station left the father with three broken ribs. Five were later jailed for their actions. Yet their commander, Okashi, told investigators while he condemned the violence, he said deploying the soldiers was necessary to make the killer pay and to create a sense of success among the fighters. He remained as commander and has been promoted since.

But Akashi is not the only Netser Yehuda commander with a dark past. This is Lieutenant Colonel Mati Shevach rousing troops before a deployment. But just over a year later, soldiers under his command left for dead. This elderly palestinian american man, Omar Assad, here lying on the ground bound and blindfolded as a soldier watches. On his death, the IDF admitted a moral failure. But no soldier faced charges for his death, and their commander faced only a reprimand. Yet still he was later promoted, now training israeli ground troops, preparing to enter Gaza, even featuring in high profile interviews with american media boasting of his soldiers enthusiasm for war. The major concern for most of the soldiers is we're going to have to stop. We asked the man previously in charge of investigating the Netzer Yehuda's abuses for the us government what he made of these promotions.

That is very bad news. That shows first of all that Israel, that the government of Israel has no intention of holding the Netsu Yehuda battalion accountable.

He says the US is not following their own laws by sending them weapons.

Of course we treat Israel differently and that really undermines our human rights advocacy in the rest of the world. The law that Congress passed and our taxpayer funded assistance is going to israeli units that have committed gross violations of human rights.

This assistance, despite the growing evidence of abuse. CNN exclusively obtained the names of three more israeli units found by us officials to have committed gross human rights violations prior to October 7. All are still operating, including the Yemam, seen here in Gaza in an operation that rescued four israeli hostages but left nearly 300 palestinians dead, according to local health authorities. The israeli military dispute that the toll was so high. As the death and destruction mounts, it is us weaponry supporting these units. Begging the question for how much longer will Israels greatest ally choose to turn a blind eye? Katie Polglaze, CNN, London.