TEL AVIV, Israel - Holocaust survivor Joseph Harmatz, who led the most daring attempt by Jews seeking revenge against their former Nazi tormentors, has died. He was 91.

His son, Ronel Harmatz, confirmed the death Monday.

Harmatz was one of the few remaining Jewish “Avengers” famous for carrying out a mass poisoning of former SS officers in an American prisoner-of-war camp in 1946 that sickened more than 2,200 Germans, but caused no known deaths. Still, the message echoed into a rallying cry for the newborn state of Israel - that the days when attacks on Jews went unanswered were over.

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In their largest operation, the group, code-named “the Avengers,” received a large amount of arsenic from Paris and laced loaves of bread fed to hundreds of SS officers imprisoned in an American camp after the war.

They said they were also planning a broad operation in Dachau and Nuremberg, but the Jewish leadership in what would soon become Israel forced them to abandon the plan.

Over the years, reports of such Jewish death squads have surfaced and several books and movies have been written. The Israeli government has often turned a blind eye to the reports.

Harmatz, who was born in Lithuania and lost most of his family in the Holocaust, spoke to The Associated Press shortly before his death and remained unapologetic for his actions and those of his group Nakam, Hebrew for vengeance.

“We didn’t understand why it shouldn’t be paid back,” he said.

Despite a visceral desire for vengeance, most Holocaust survivors were too weary or devastated to seriously consider it, after their world was shattered and 6 million Jews were killed during World War II. But his group of some 50, most young men and women who had already fought in the resistance, could not let the crimes go unpunished and actively sought to exact at least a small measure of revenge.

Undercover members of the group found work at a bakery that supplied the Stalag 13 POW camp at Langwasser, near Nuremberg, and waited for their chance to strike the thousands of SS men the Americans held there.

It came on Apr. 13, 1946, when three members spent two hours coating some 3,000 loaves of bread with arsenic, divided into four portions. The goal was to kill 12,000 SS personnel, and Harmatz oversaw the operation from outside the bakery.

In a story published last month, Harmatz told the AP the goal was simple.

“Kill Germans,” he said flatly.

How many?

“As many as possible,” he quickly replied.

A recently declassified U.S. military report obtained by the AP only added to the mystery of why the operation did not kill Nazis, because it shows the amount of arsenic used should have been fatal to tens of thousands.

After the war, Harmatz, who went by the nickname Julek, immigrated to Israel, where he worked at the Jewish Agency and was director general of World ORT, a Jewish educational organization.