Unnatural Death by Dorothy L. Sayers (1927)

An elderly lady suffering from cancer dies suddenly but her young doctor is suspicious. His patient was a tough old lady and he had given her another six months to live and here she is, dead, only days after his prognosis. He refuses to sign the death certificate with but no evidence of foul play after an autopsy, he is left looking like a fool.
Three years later, the doctor chances to overhear Lord Peter Wimsey and his good friend, Detective-Inspector Parker of Scotland Yard,  discussing a similar case as they sat at an adjacent table in a restaurant. The doctor interrupts their conversation to introduce himself and tell them of his own experience.
Lord Peter, of course, is immediately interested.

‘Do you know,’ he said, suddenly, ‘I’m feeling rather interested by this case. I have a sensation of internal gloating which assures me that there is something to be investigated. That feeling has never failed me yet - I trust it never will.’

And so Wimsey gets involved in the affair, enlisting the reluctant Parker of whom he says,
‘He’s the one who really does the work. I make imbecile suggestions and he does the work of elaborately disproving them.’

Evidence of foul play begins to show itself once Wimsey gets involved with the death of the old lady's maid and then an attempt is made on Wimsey's life. However, although there is a suspect, there doesn't appear to be a motive.

The banter between Wimsey and Parker, who later marries Wimsey’s sister Mary, is very entertaining. Parker is conservative and formulaic whereas Wimsey is as his name implies - whimsical.

Wimsey wants to introduce Parker to ‘a friend of his,’ ‘- rather an experiment...quite comfortably fixed in a little flat in Pimlico...’
Much to Parker’s surprise, Miss Climpson was not a love interest but a middle-aged single lady with Edwardian-styled iron-grey hair, covered by a net, who would have made a very good lawyer but had never had the education or the opportunity.
She was a kind of ‘inquiry agent’ for Wimsey: his ears and his tongue. Wimsey believed Miss Climpson to be ‘a manifestation of the wasteful way in which this country is run,’ and that women like her who are ‘providentially fitted’ for work carried out by 'ill-equipped policemen’ are allowed to go to waste.

So far I’ve read seven out of fifteen of Sayers’ Lord Peter Wimsey books. Unnatural Death is the third in the series and although it’s not her best it’s still a jolly good read.
Sayers doesn’t write down to her readers. Her characters and plots are rich and full of detail with frequent allusions to literature and sundry interests leaving the reader with a knowledge of such diverse topics as advertising, bell-ringing, Shakespeare, and architecture.

I chose this book for No. 9 of my Christian Greats Challenge: A Good Old Detective or Mystery Novel Mystery. J.I Packer called this type of novel, 'stories of a kind that would never have existed without the Christian gospel. Culturally, they are Christian fairy tales, with savior heroes.'

Towards the end of this book, Wimsey is looking for Miss Climpson and stops at the church she attends during the week to see if she is there. Not finding her, on impulse he asks the priest, Mr Tregold, for advice on a moral problem, a ‘hypothetical case,’ that involved killing a person who was going to die, who was in awful pain, kept under morphia etc.

‘I know you’d call it a sin, of course, but why is it so very dreadful? It doesn't do the person any harm, does it?'

‘I think,’ said Mr Tredgold, ‘that the sin - I won’t use that word - the damage to Society, the wrongness of the thing lies much more in the harm it does the killer than in anything it can do to the person who is killed. Especially, of course, if the killing is to the killer’s own advantage...’

The Lord Peter Wimsey crime series are in print and available here.