God created man. God created man with free will; to choose right or wrong, righteousness or sin. When one chooses sin it's their own doing, God is pure righteousness, He has no part in sin nor does sin have any part of Him.
You could make a case for god creating some killers. People define sociopaths as someone who basically lacks emotions/empathy. They are atavistic. In a religious sense it's defined as they lack a soul. That's not something someone consciously does, it's how they are born.
No. God created us and have us free will. So we choose how we act, who we love, etc. He knows the outcome of everything already, but he doesn't intervene on earth. The main reason we have free will is he wants us to worship him and love him by our choice not by His force. Sadly this means people will do heinous things to others. At least this is my belief on this.
You see, God created each person with a free will. They can do what they choose. God does have a perfect plan for every person, but it is our choice to obey and love Him - to follow His plan. In the case of these killers, they chose to disobey God for whatever selfish reason. This was their free will acting, not God. However, this does not mean that God can't use that person's decision for good.