I think it'd make that part of the plot stronger, but I'm afraid it'll just seem weird to have a book that's mostly a 50-50 split between two characters dip into a third head for a stray scene here and there.

It could be weird, or it could be essential. How is the book structured? Is it all chapters, or is there a part one, two, three, etc.? Could you use the villain sections as transitions between parts? Deliberately set them off so they don't feel as random?

(My mind is thinking of It, and how King used the Derry Interludes.)

Chapters. In my own head it's divided into three acts, but I'm not planning to divide the book itself that way. Well, except that there's a bit of a time/space break between Acts II and III, so I'll need to do something to show that we're in England and it's November now. And the villain actually dies near the end of Act II.

And even if it weren't for the whole dying thing, the places where I feel like I need the villain POV don't fit into obvious transitional points.

the places where I feel like I need the villain POV don't fit into obvious transitional points

Do you ever do scene breaks within a chapter? (I feel like I should know this, but I can't remember.) You could switch to villain's POV that way a couple of times. Just be sure you've set it up so it doesn't feel abrupt, even if it only means a character mentioning his name in the previous scene or something.

Do you ever do scene breaks within a chapter? (I feel like I should know this, but I can't remember.)

Yep, I do. And if I'm switching POV, even if it's a continuous scene, I always put in a line break to prepare the reader for the transition.

I think I'm just gonna try it. If it doesn't work, I can just take it out.

I'm having trouble setting up my clues, y'all. How big should they be? Because the last thing I want is to create a giant "No! Duh." But the days when a broken cigarette can solve(excuse me, put down) a case are long dead.

Witness: Are you going to look for clues?
Detective Howard: The body in the basement is sort of a big clue.
And I know my P.I. can't be present for everything that happens with the police investigation, but her brother is a patrol sargeant...maybe she can nag Little Bro. She also made a "connection", in Xander-speak with the guy that caught the case, but he can't give her too much info, right?

cereal: How many red herrings? It's partly my own fault for giving this thing a cast the size of Guam, but you know...I know a lot of folks and they know a lot of people, so that feels real, but I don't know how to manage them.

A couple of red herrings are nice.

I suppose. They call 'em whodunnits not dunkers, right? For those few not Homicide-literate, a dunker is like, well, two cowboys having a shootout or something...the one not on the ground did it. A guy running around in a bloody shirt saying "And I'd do the bitch again!" Dunker. Only people like me read those books.

(half a drabble)

Cowboy on the ground in Mainstreet. Gun-fanning opponent stands with smoking gun, black hat tilted, silver gleaming.

Homicide cop dunks doughnut, observes to partner: "Winchester on Stable rooftop, right?"

Partner: "Heart attack."

HC: "Suppose we'll have to examine the body to settle this."

Partner: "What is this? CSI? He's dead. Pass the crabs."

Hee, hee. "Got yourself a stone dunker, bunk." Definite black under your name.