The Judge Hutchinson's Gavel

During a murder trial the defendant proves beyond a reasonable doubt that he is an extraterrestrial alien, who arrived to Earth with a mission to study humans, and the death of the victim was the result of his psychological experiment. Suddenly the alien turns the table on his accusers and now the entire humankind becomes the defendant. Considering that the alien possesses ultimate superpowers, the outcome of the trial might change the course of human history very drastically.