The question was one of many debated Thursday night by retired South African Judge Richard Goldstone and former Israeli Ambassador to the United Nations Dore Gold at a special event hosted by Brandeis University and broadcast live over the internet.
It was of particular significance because it was one of the 36 incidents named in the Goldstone Report as evidence that Israel had committed war crimes in Gaza.
The report, which comprised the findings of a fact-finding mission to Gaza led by the judge, was endorsed by the U.N. General Assembly earlier in the day.
"The one attack that affected me was an attack on a mosque where there were 300 people praying," Goldstone told the audience Thursday evening. "They were attacked by IDF ground forces, they fired a missile, 21 people were killed.
There was no question of ammunition being kept there, no secondary explosion. There was no basis in international law for the attack, even if ammunition was stored there, in fact -- there is no basis for bombing during a service," he said with what appeared to be anger. "Bomb it at night if you want, but there is no justification for bombing it during a service."
Goldstone went on to say that he also could not understand the "complete demolition" of the American School in Gaza City, which he described as a bastion of anti-Hamas sentiment. "I still would love to know why the IDF chose the American School," he said. "Hamas hated that school. It made no sense."
Gold responded with a flat denial that Israel had had anything to do with attacking the mosque at all -- and in fact, of the 36 incidents recorded in the Goldstone Report, "there are 12 that the Israeli army never heard of," he said.
"But I trust the Israeli legal system to get to the bottom of it," he assured the audience, listing investigations by the attorney general's office, the Supreme Court and the IDF as reasons that Israel does not need to launch another independent investigation, as urged by Goldstone.
"As far as the mosque is concerned," Gold said, "the Israeli position has been that the mosque was not attacked by the IDF. The challenge is in reconstructing a reality that no longer exists," to figure out what really did happen there.
"Do we know that munitions exploded in the mosque itself? Do we know who were the people who were in the mosque at the time, who were killed? There are many questions. But I am telling you this: Israel did not attack that mosque."
The former Israeli ambassador's reply was rejected out of hand by the retired South African judge. "We found the remnants of the Israeli ammunition," scoffed Goldstone. "And the tungsten squares that were pulled out of the wall in my presence. It's like the story of the man charged with rape, and he denies he was guilty, because he says she consented..."
The two men sparred for approximately 90 minutes, with generous amounts of time allocated for questions from students in the audience.
Only once did hecklers interrupt, and that incident was quickly and firmly squelched by the moderator, who reminded the students that the school is devoted to enforcing the American Constitutional right to free speech..