Keith R.A. DeCandido is the author of hundreds of books ranging from Star Trek to Leverage to Supernatural. I've read a dozen or so of his books and enjoyed almost all of them. I think my favorite is his I.K.S Gorkon/Klingon Empire series which chronicled the adventures of a crew of Klingons on a four book mission to seek out new life, new civilizations, and kill them. He's a great writer of enjoyable characters, straightforward plots, and having developing events mixed together in fascinating ways.
SCPD which stands for "Super City Police Department" is a novel which is set in an original world where superheroes protect Super City from all manner of horrible monsters. However, this particular city of heroes doesn't have the level of trust and respect which accompanies heroes like the Justice League or Avengers. Instead, they carry a level of burning low-level resentment from the police and local government for hogging the spotlight as well as botching investigations.
The series seems inspired by the series Gotham Central by Ed Brubaker and Greg Rucka. That series was notable for showing the perspective of Batman from the Special Crimes Unit. SCPD is set in a lighter, softer city like Metropolis. Still, the premise of the book is anything but a light one as it is about a superpowered serial killer run amuck. A killer which the superheroes are completely unable (or unwilling) to do anything about.
The protagonists of the book are likable enough but generally fall into the category of archetypes rather than deeply involved characters. Still, I love the way they play off well against one another. The primary two are the classic combination of the older grizzled cop who has seen it all and the idealistic yet ambitious young female detective who is eager to make a difference. They play off well against one another and the moments where they're just getting to know one another's style of doing things is some of the best parts of the book.
I saw the "twist" ending coming from a mile away. However, the mystery isn't the major sticking point but how it expresses itself across the lives of multiple perspectives. The Claw is an individual who has terrorized the city multiple times but he's a figure who is arguably not responsible for his actions. Superheroes are prone to making more excuses for him than the public which he menaces and we get a nice little reflection of how the former's treatment of villains like, say, the Joker would come off to the people.
I was a big fan of "everyman perspectives" and the reason they succeed is on the strength of the characterization as well as giving a new perspective to extraordinary events. That is the case in SCPD. I think the city could have been developed a bit more and the superheroes a bit more likable but given the nature of the case, I suspect Keith didn't want them overshadowing his collection of Muggles in a world of superhumans.
In conclusion, SCPD is an enjoyable afternoon read. Notably, this is a series which "jumped companies" and continues after the events of SCPD under a new series name and company in Super City Cops. I haven't checked out those books yet but I am inclined to do so. This is the equivalent of a hamburger and fries sort of fiction and that's sometimes just what you need.