Does God allow evil?

Question: 

Why does GOD allow bad things to happen - like murders and people to exist like Hitler?  

Answer:

There are 3 ways to answer your question:

I think Father John Corapi answered this question well in one of his talks: 

Question: Why does God allow evil to happen?

 Answer: So he can bring about a greater good. If you do not believe this, ask yourself this simple question. What is the greatest evil ever perpetrated by man.? Answer the Crucifixion of the innocent Son of God. Question: What is the greatest good ever accomplished for man. Answer: Our salvation purchased for us by Jesus death on the Cross. It is because of Him we are redeemed and are able to be saved. 

Here is 2nd answer to your question:

God allowed us out of PERFECT GOODNESS to have free will. (sin and suffering came because of free will)
God allows sin and suffering (because of free will) because He Is Perfectly Good.
Suffering (and HOW we suffer) brings about greater good (because of free will), its called 'redemptive suffer.'
His Own Son, Who is All Good, suffered horribly for us (because of free will--His and ours). If He can suffer to offer glory to God, so can (should???) we.

Here is a 3rd answer by Dr Peter Kreeft (great Catholic Philosopher) who offered this explanation:
1. There are no good people "all have sinned and fall short of the glory of God (Romans 3:23)."

2. There are no bad things, at least for those who love God  "We know that in everything God works for good * with those who love him, * who are called according to his purpose (Romans 8:28)."

3. God has given us free will: "I have set before you life and death, blessing and curse; therefore choose life, that you and your descendants may live" (Deuteronomy 30:19).