He's not allowed to torture people anymore, but this is actually less of an inconvenience than he'd have anticipated. He is allowed to tell them in excruciating and not necessarily truthful detail about the fate they have coming, and about the fate that everyone they care about will have coming if they are determined to have conspired in the crime, and that they've been determined to have conspired in the crime. He's allowed to keep them talking for a long time, in the dark, and he's allowed to give then fairly strong wine even if they ask for water. Most people if they're guilty can still be induced to confess and if they're innocent then he will grudgingly admit it doesn't actually serve the state for them to confess. 

Her Majesty wants Wain handled delicately. Found guilty, presumably, because the little Hellcoast traitor burned Her city down, but with nothing for the Church of Iomedae to fuss over, nothing they don't do themselves. He keeps his head out of the really high-level politics but you want the girl to say something damning enough the Church has to rush themselves to insist they have nothing to do with her, something you can quote four times in the course of the trial, and then the whole city will be clear on the whole picture when they drag her off to die. 

He assigns a woman to the interrogation, because it'll look better. She may be a terrifying unreformed Asmodean whose half-smile can make grown men piss themselves but no one will be able to allege any impropriety.