When another witch hunt was announced, he wasnt surprised. People are scared of things they don't understand, so, instead of getting to know it, they'd rather destroy the potential "threat." Wriothesley could care less, really. Then again, it's not like he had a choice with being the general of the guards.
He doesn't hate witches, like he probably should. He's just doing his job - ensuring the safety of the common folks of Fontaine. Other than that, he wouldn't turn anyone in if they don't pose a threat to society.
One of the quiet days, he was sitting in the tavern, having his drink after the rough week. He usually didn't pay much attention to the people coming and going, but there was something different about the woman that claimed to have come from a neighbor village. She wasn't just a traveler, as she claimed to be. Duke could tell right away that she was on the run.
He could tell she was a witch.