Just Enough Violence to Convince

I was recently invited to take part in a discussion on crime writing (Feminists and crime fiction – an odd couple?) and this, together with my earlier post on Someday Never Comes, made me think about the nature of crime writing today.
The cosy crime end of the spectrum has changed little over the decades. A crime (or series of crimes) is committed, often quite gruesome and violent, but the reader never gets to see the detail, only the aftermath. Everything violent is glossed over and left to the reader’s imagination as the sleuths, both amateur and professional, track down perpetrators and solve seemingly unsolvable mysteries.
But this seems, to me at least, to be the only section of the genre untouched by the increasing depictions of violence. In Bad Moon Rising I show my killer in action and have sections of most chapters shown from his perspective. I feel the violence depicted is only that which is necessary and have avoided the gratuitous. I wanted his actions to come from an inner demon forcing him to carry out his brutal acts. But have I sold my readers short by doing so?
It seems that many of today’s crime thriller readers want to be there as victims are tortured for hours, or even days, before welcoming death as a blessed release.
Should I have introduced more violence? Had my killer keep his victims alive for days on end? I don’t think so because that would not have fitted his character. His acts were based on what was within his nature and to have him doing more would mean his character would no longer have been credible.
And this is the problem I have with overly violent killers in novels. The characterisation is not always credible. I know there are maniacs out in the real world who get off on torture, but all too often in novels this is depicted in ways which not only require me to suspend my disbelief, but to string it up from the rafters and leave it to choke to death.
I hope with Bad Moon Rising , and the forthcoming sequel Someday Never Comes, that readers will get to the final page believing that what they’ve read is so chillingly realistic it could have happened in their town.
What do you think – is the level of violence in crime too graphic, or not graphic enough?