Unpleasant characters in a mystery

It's fair to say that a good many modern crime novels seem to be populated with an array of unpleasant characters. But even where you have a book with (say) an appealing detective, it's quite common to find that the characters you dislike are in the great majority. But is this inevitable?

In a whodunit, you need to have a range of people who might conceivably have committed the murder. Years ago, common motives were inheritance, and the difficulty of obtaining a divorce. Plenty of books featured people who seemed amiable, even though they turned out to be murderously inclined. The culprit in Agatha Christie's The ABC Murders is but one example.

But nowadays, motives are (I suggest) more often rooted in character flaws than perhaps was the case in the past. And perhaps this means that the characters themselves are unlikely to be attractive, at least below the surface.

It's an issue that vexes me with my own books. One of my recent novels therefore was based on the premise that an appealing person might have a good reason to commit a terrible crime. But more often, I find that almost all my suspects have their dark side. This is true of The Serpent Pool , for instance. And I do wonder about the views of readers. Is it enough to have a small number of appealing characters? Or do you like the (seemingly) nice guys to be in the majority – and, if so, how do you respond when one of them turns out to be a murderer? Or does it really not matter, as long as the story holds your interest?