I see mention of free will in comments below as an answer to why God created evil. That is a religious answer, but not a scientific one or even a spiritual one for that matter and it doesn't address the problem.

God created a great white shark - a "killing machine" and yet it kills to eat. Few creatures not named Man kill for pleasure. But we do.

Why did God think less about man than about sharks, tigers or crayfish?

Religion tends to be a one life answer to problems that require a much longer view to resolve. Half the world today believe we live more than once. Why? Do they see things in our past that answer the questions of who we are today and why?

I believe they did, but most traditional religions started with one God and when you have only one person to hold accountable for everything - answers begin to repeat and lose focus.

Evil is in all of us - but 98% of us control it with love, empathy and discipline. Given provocation a kind person will turn mean to survive or protect others, but will revert to their true nature. Evil people do not.