Brochas Daf Yud Tes amud aleph

One who speaks (ill) of the dead, is as if he has spoken to a stone. 

R. Yehoshua ben Levi says, one who speaks (ill) of a Talmid Chocham after (he lies) on his bier, will descend to Gehinnom. As for those who turn to perversion, Hashem will drive them with the workers of iniquity (to Gehinnom.) Peace be to Israel. Even where there is peace for Israel (i.e. peace for the Talmid Chochom after his death) Hashem will drive them (that disparage him) with the workers of iniquity (to Gehinnom)

The Maharsha explains the difference in language. A Talmid Chachom post his death is still called alive (because of his Torah). By employing the language of lying, it is as if he lies there alive.

The Ben Yehoyada amplifies on the final line of the brysa. By disparaging the Talmid Chocham, he attempts to distort the Heavenly scales that weigh up the merits of the deceased against his errors. When the Talmid Chocham passed away, there was Shalom because his good deeds outweighed his bad ones. By attempting to pervert the course of justice, the "worker of iniquity" reduces Shalom in the world and increases his own bad deeds, thus meriting Gehinnom.