Would the sins perpetrated by various religions happen whether or not they believed in a God?

So a lot of people argue that God tells them the truth. He or She tells them what to believe. However, I’m wondering whether it matters if they believe in God or not. Would they behave the same way if they didn’t have a God? Would they believe the same things if they didn’t have a God?

Please name the sin perpetrated in God’s name and say why you think it would or would not happen if there were no God.