This genre was my favourite but I find the books are getting way too trashy. (I used to be a criminology student so I'm a snob about this stuff, lol.)
But for some good reads, anything by Jack Olsen. An excellent storyteller - especially try "Doc".
Another very well-written book is "In Broad Daylight" - sorry I can't remember the author's name. If you watch A&E you may have seen this story on the "City Confidential" series (the town of Skidmore, Missouri).
If you can stomach it (I have kids so I'm sensitive to stories involving children) there's also "What Lisa Knew", about the Lisa Steinberg case. A lot of focus on "battered spouse syndrome" defence that was pioneered in this court case.
One more and I'll stop blathering on - "Rock a Bye Baby" (this is a Canadian book so may be hard for Americans to find) - very thoughtful, sympathetic read about Canada's first woman who was deemed a "dangerous offender".
These are all excellent books for anyone interested in this kind of stuff. And, of course, if you must read about Charles Manson, stick with Helter Skelter.