Did Humans really commit Elf Genocide

Ok this epsiode was a bit disappointing because I really wanted to see what happened to Yuno but same cliffhanger at the end that was foulplay. Anyway onto the main topic. We got more info about what happened to the elves in the past but not the full story. They believed humans were the ones that attacked them but there werent any visible indications that it was them. We saw no humans but light magic being used to kill them off and someone saying it was the humans attacking which was probably an assumption. This is the info we got about the elf genocide from this episode from the situation: Someone attacks the elves and committed genocide. This person used light magic and there was also a barrier with magic cancellation. It is assumed that the people attacking were human. Patry the antagonist assumes that its the human who is the brother of the wife of Licht. Patry sees Licht activate forbidden magic and assumes it was ressurecttion magic to save the elves. If you went to a quick conclusion without thinking yeah it would be the human attacking the elves for devious reasons but thats not a fact its an assumption. Only the first two are true facts. It is possible that Licht himself committed the genocide. Licht was there at the scene but he did nothing to save his fellow kin. You could say he came afterwards but that still doesnt make sense. He was there right when the attack stopped and there werent any humans coming to confirm the complete annihilation of the elves? I believe Licht was the one who killed the elves but what ponders me is the motive. Why would he do such a thing? Welp thats my theory of what possibly happened in the Elf Genocide. If you guys have any thoughts about the event or about my theory please feel free to comment.