There is no such thing as a “perfect crime.” The Day of Judgment will see that every transgression of the moral Law will receive just retribution. God will bring every work to judgment, including every secret thing whether it is good or evil. What a fearful thing for guilty sinners and for evil spirits. No wonder demons tremble at His name.
It shall come to pass in that day That the Lord will punish on high the host of exalted ones, And on the earth the kings of the earth. (Isaiah 24:21)