Better to say "that you knew was guilty".
Kinda reminds me how we finally learned years after he had died that Upton Sinclair had actually known that Sacco and Vanzetti had been guilty but chose to write a class-war mongering defense because he knew it would sell better with his European audience.
I actually have a newspaper where a front page story is how Sacco and Vanzetti’s appeal was finally denied (and as a consequence they were executed).