Remember when paperback books were short? This one clocks in at 96 pages, though since the text begins on page 5, that makes it even shorter. You have to take into account, however, that at this time (1960) the folks at Avon books was apparently experimenting to see just how small they could make the type before readers marched on their offices with torches and pitchforks.
Just by looking at the cover and the author's name, you've probably already figured out that Angel is anything but. She's the wife of Nick Gavin's best friend, Fred, and Fred has just been shot to death. The cops find Nick in the front yard with the murder weapon in his hand. He's not arrested, so he starts to try to figure out what's going on. He's only in town because Fred wrote him and asked him to come, and he knows something's up.
The night after Fred's death, Nick visits Angel, who's definitely not grieving. Before long, well, you know what happens. You'll also figure out what's going on long before Nick does because he clearly hasn't read enough Gil Brewer books. It doesn't really matter that you're ahead of him, however. The book is a blazing fast read, and Brewer manages to throw in several little twists before the end. It's worth having for the cover alone, though not at the prices I've seen on the 'Net. Check it out if you already have a copy in your library.