he said he sensed lyrra's death, and thew only other person we know can do that is tetzel.
Theres a difference between sensing and reading a book. Besides, we've gone over the whole Tetzel is Gauis thing many times and it just doesnt work.
As I see it The PS was a tool of Tetzel not directly, but rather Tetzel used the fear the PS created to further control the people. We know he has been spreading rumors about the PS, but theres been no real proof of any direct control.