According to Psalm 14:1, who says in his heart, "There is no God"?

Answer: The fool

"The fool says in his heart, 'There is no God.'" The same line opens Psalm 53.

“For the choirmaster. Of David. The fool says in his heart, “There is no God.” They are corrupt; their acts are vile. There is no one who does good.”— Psalm 14:1 (BSB)