NoDictionaries   Text notes for  
... et hactenus adito discrimine, [ne] auctor dubitaret[ur]. tum pavore...

"that the author/perpetrator could not be doubted"; "ne" should be part of the text, although this is a negative result clause, which would ordinarily require "ut non," unless Tacitus wants to imply that the purpose of Agrippina's survival was to expose Nero's criminal act.