Following is the formal disproval of the creator GOD. This is the GOD mentioned in all the Abrahamic religions like Christianity, Islam and Judaism.
Assumption: GOD, who is the creator of everything, have all of the following characteristics at the same time.
1. Omnipotent - Having unlimited power
2. Omniscient - All knowing
3. Omnibenevolent - All good
Statement to disprove: "If the creator GOD have all of above features at the same time, HE cannot be good. GOD should be evil."
Example: Tsunami in 2004, which killed more that quarter of million people in south east Asia.
Disproval using example:
God knew that the Tsunami is going to happen. (He is Omniscient)
God had the power to stop the Tsunami(Omnipotent)
Yet He didn't do anything to avoid the deaths of hundreds of thousands humans,eventhough most of them are believers of GOD.
Hence He cannot be Good. He should be evil.