Talmage Powell was one of those guys who never cracked my Top Ten list, but he wrote some good paperback originals (try the Ed Rivers series, for example). The Girl Who Killed Things is a pretty good try at a Gold Medal book, and it's certainly influenced by James M. Cain (the ending is strongly reminiscent of Postman, at least to me), but it's not up to Cain's level. It's a good book, just not a great one.
Enos Drake goes to Atlanta on business and meets Vi. He thinks she's perfect (he hasn't read any Cain or any Gold Medal books). Drake's from an old, wealthy family in his small town, and he doesn't ask Vi about her background before they marry. When he gets into trouble with a conniving business partner, Vi has the perfect solution: kill the guy. It would be wrong for me to tell you what happens after that. Let's just say that things sort of go as planned, and then they don't. And after they don't, it's downhill from there. You know what I mean.
Good pacing, some nice twists, and some nice swampy local color. Worth checking out.
Update: In a comment below, Todd Mason asks about Zenith Books. So I consulted my copy of Mass Market Publishing in America, edited by some guy named Crider, and read the Zenith article, written by some guy named Pronzini. He says that Zenith was born in 1957 and lasted a couple of years. It was created from the assets of Lion Books, so some titles were originally intended for that imprint. Best-known title: Damon Knight's The People Maker.