Any Israeli missile would have guidance systems on it, where as the rocket from the cemetery would be a fire and forget type. So it seems unlikely to me anyway - that it would have been from the Israeli side.
Neither side will admit it was their fault - ever - no matter how much proof there is.
Gaza city is being flattened as prescribed, and Israel has a strangle hold on them - which they cant get out of - other than to increase the reach of the war and get Iran / Hezbollah involved etc. Hamas appear to not have thought this through very well. Hopefully sleepy Joe can get a cease fire, Gaza has been taken back to the stone age - and they can spend the next 20 years re building it - while Israel built a steel wall with remote controlled guns so they dont fly over the top again