Evil people die all the time. If it was clearly a miracle (נס) or if he was someone threatening our existence, it might be an occasion for the gedolim to declare a yuntuf. The individual killed was a soldier fighting Medinat Yisrael, who in accordance with traditional of soldier everywhere and everywhen, specialized in killing civilians (technically illegal under international law, especially if your side loses the war). Since Nazi soldiers died on every day of the year (not heard, they lost millions and there are less than 400 days, so it is as mathematical certainty that every day is the anniversary of the death of a Nazi). Note than during World War II, which was a real threat to our existence, we didn’t cancel tachnun to celebrate the death of a Nazi. And the act he was killed in a very ordinary way by the Israeli forces makes it a stretch to say it was a miracle..
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