He grows up.
Menas Karam is strict but consistent, and Milites has always been a quick learner.
Milites questions him, at first. His father wouldn't have minded. But he learns quickly enough that Menas Karam is not nearly so patient as his father was. He stops questioning him.
Don't you want the man who killed your father to get what he deserves, asks Menas, and -- it hurts to know that even after his adoptive father paid for a Speak With Dead spell, even after his father identified the killer, he still managed to flee the town before he could be executed. It's not right that his father is dead and his father's killer is free.
(He wakes up before dawn every morning in a cold sweat. He tells himself it's just a nightmare, it doesn't mean anything. Sometimes he believes it.)
Menas Karam gets him a position as court-assistant. He's the youngest court employee by nearly five years. He works fourteen hour days. Their courts are overstretched, and Zone of Truth isn't perfect anyways -- Abadar's Truthtelling would be better, but there definitely aren't enough clerics of Abadar in the city to cover every trial, even if the courts could afford the fees they demand. They fall behind, and he starts working sixteen hour days and sleeping six hours; it's not as if his sleep is ever very restful.
Sometimes, when someone clearly guilty manages to defeat a Zone of Truth, he manufactures evidence to ensure they're convicted. Someone has to keep the streets safe, and none of his colleagues are willing to do it.
(One of the guardsmen asks him if he's okay. He tells them he's fine.)
There's some sort of drama in the capital and a quarter of his colleagues are fired for no clear reason. He tries to work twenty hour days and wakes up in a cold sweat in his office three nights in a row. It's a stupid failing, and he owes it to the city to be better, but telling himself that doesn't help. He takes home some work to his adoptive sister -- she's brilliant, really, it's a shame the courts would never consider hiring her. It helps, but not enough.
He points out that if they stop trying to have everyone go through a Zone of Truth interrogation trials would move quicker. They all know it's not reliable enough anyways. The rest of his colleagues breathe a sigh of relief, and they stop using it outside of exceptional circumstances. The trials he handles have a near-perfect conviction rate. He knows exactly what to tell every judge to guarantee they convict, and he can make sure that whatever evidence they need is there.
(A crying mother of three swears to every god she can name that she didn't do it. A twelve-year-old is escorted wordlessly out of the courtroom. A witness's story is a touch inconsistent, but -- he's an upstanding member of the community, the most likely explanation is that he misremembered a minor detail. Of course not every detail is going to line up in every case, that's what he's here for, making sure that even if a few details don't line up the criminals are still punished.)
He keeps a holy symbol of Iomedae on his desk. It's not common, not in this part of Taldor, but -- she's the goddess of defeating evil, and he needs all the help with that he can find.