GE 3:1-7, 22-24 God allows Adam and Eve to be deceived by the Serpent (the craftiest of all of God's wild creatures). They eat of the "Tree of Knowledge of Good and Evil," thereby incurring death for themselves and all of mankind for ever after. God prevents them from regaining eternal life, by placing a guard around the "Tree of Eternal Life." (Note: God could have done the same for the "Tree of Knowledge of Good and Evil" in the first place and would thereby have prevented the Fall of man, the necessity for Salvation, the Crucifixion of Jesus, etc.)
GE 4:2-8 God's arbitrary preference of Abel's offering to that of Cain's provokes Cain to commit the first biblically recorded murder and kill his brother Abel.
GE 34:13-29 The Israelites kill Hamor, his son, and all the men of their village, taking as plunder their wealth, cattle, wives and children.
GE 6:11-17, 7:11-24 God is unhappy with the wickedness of man and decides to do something about it. He kills every living thing on the face of the earth other than Noah's family and thereby makes himself the greatest mass murderer in history.
GE 19:26 God personally sees to it that Lot's wife is turned to a pillar of salt (for having looked behind her while fleeing the destruction of Sodom and Gomorrah).
GE 38:9 "... whenever he lay with his brother's wife, he spilled his semen on the ground to keep from pr...