Antisemitism: Jews killed Jesus accusation (Deicide)
The accusation that the Jews have a collective guilt for the death of Jesus was a key form of Christian antisemitism. It was historically used to stir populations up against the local Jewish community. It usually resulted in pogroms where many Jews were murdered. The accusation was rejected by the Second Vatican Council (1962–1965).
The accusation can still be seen in social media where it is used to try and stir up hatred against the Jews from Christians.
Other useful sources: