When the “good” Srs of St Mary of Namur were teaching me, they told us “the Jews killed Christ”...pretty common belief it seems
You are correct. The answer must always be that the wicked Jews killed Jesus.
There was a trial held in Troyers, France on 12/23/1974, called The Jesus Trial, and it considered the question of just who killed Jesus. 3 justices presided and the Chief Judge Pierre Bondouaire rendered the verdict: the Romans were guilty - the Romans killed Jesus.
A related optional question: when Jesus was killed, did he actually die?