Reminds me a lot of Rogue Male by Jeffrey Household in its focus of a person trapped in an inescapable situation that is explained ever-so-thoroughly. The difference between that taut thriller and this are the additions of a crazed infatuation of a romance and a framing device that feels like when a studio makes a movie reshoot the ending to make it happy. I just looked it up and it was based on a novella, so it makes sense the ending was expanded. But well-written noir to the max.