In relation to Story involving Islamic terrorists planning an attack on a stadium, I mentioned a contemporaneous series to the book I am seeking there, but couldn't recall the title. From my experiences on the SF&F SE, I'm a bit hesitant to leave that hanging because there's inevitably an "answer" that's identifying the reference rather than the book I'm actually looking for.
It is a series with at least two books, because I read the second one. The main character is a female detective, I'm pretty sure very formerly with the police. Prior to the events of the book (I think, prior to the first book), she was a police officer who got captured by a gang of criminals, who hold her in a house and abuse her (sexual assault, cigarettes put out on her, and something involving a beer bottle are what I recall). At some point, she is able to make her escape, I think due to an abuser getting drunk and passing out, allowing her to get ahold of a broken beer bottle, which I think she shoved into her captor's eye in the course of her escape. In-universe, it was noted to be an extremely bloody and brutal scene as she killed everyone in the house, but she was acquitted for it basically being self-defense.
Said abuse is far enough back in the series that it only showed up in occasional traumatic flashbacks, and people referencing it, painting her with the image of a violent woman. Other than that, the details are sparse. I remember she had a boyfriend, who I don't think she'd married by the end of the second book, and that she lived in an apartmnent. She's a good detective, carefully gathering evidence is a systematic fashion. I don't remember what case she was solving, although I have a plot that might relate. Since I don't know for certain that it's the same book (and yes, I recognize the irony of bringing this up in the midst of trying to clarify another memory), I'll put it in the next paragraph.
If it is the plot I'm remembering, she's watching the U.S. President for infidelity, and accidentally becomes the last person to see the President's mistress before said mistress is found dead, apparently the victim of a serial killer. In the course of unwinding the plot, she finds there's a string a suspicious deaths among the President's lovers, but also eventually learns that he's not behind them. One of those murders was blamed on a jailed serial killer who collects body parts of his victims, and is rather put out that someone pinned a copycat offense on him.
It eventually turns out that it was the President's wife who's been killing the girls with the help of the the President's political aide, who's desperate to bury any scandal. I believe it was left ambiguous as to whether the President fully knew what his wife had done, but that he should have known something was going on.