There's the threat of alligators [or crocs?] the whole way through this book. And Bob is such an unlikable guy you start to hope one of them might crawl out and eat him.
But he's charismatic too, in a weird, shouldn't really work kind of way. I like this about Leonard, the way he puts people like Bob in there, people you can't turn away from even when he's trying to sleaze onto the main female character. A definite plus. Actually, she's not just the main female character, she's the main character full stop. There's the other cop, who seems like he might get together with her, but it's mostly the woman's show. She's a bit like Karen Sisco from Out of Sight...I only saw the movie of that story so I'm not sure if the name's the same in the book...tough yet compassionate, and not crazy enough to go for a guy like Bob, no matter how much cash he has.
Best part of this comes about two thirds of the way through. I won't spoil it but it's a plot twist that really took me by surprise, and only Leonard could really pull this kind of thing off.