Why is someone killing British officers' wives?

The Last Kashmiri Rose by Barbara Cleverly is her first mystery, and as such is a very creditable effort. It is set in India in 1922 and the protagonist is WWI veteran Joe

Sandilands, a Scotland Yard detective on temporary duty in Calcutta. The young wife of a British officer stationed at Panikhat, a military post fifty miles from Calcutta, has apparently committed suicide. The Governor of Bengal's niece, whose husband is also stationed at Panikhat, who was friends with the dead woman, and who has no confidence in the investigative abilities of the local British cop, prevails upon her uncle to assign Joe to look into the death.

Joe, with the invaluable help of an Indian police sergeant, establishes almost immediately that the wife's death was not a suicide. (But you knew that before I told you, right?) Not only was it not a suicide, but over the last ten years five other station officer's wives have died, all in the month of March—there was a time out during WWI—all in a way that was ruled as an accident at the time, each in a way that the victim most dreaded. I.e., the woman who had a phobia about water drowned; the woman who was terrified by snakes was bitten by a cobra.

So we have a diabolical serial killer on the loose. Who is it? And why these particular women?

We follow Joe as he uncovers clue after clue. Because he is bangers-and-mash British, he learns about India and its customs together with the reader. He is even able to have a brief sexual liaison with the governor's lovely niece. And, of course, he solves the mystery.

If this sounds like the sort of thing that appeals to you—an exotic setting, a complex puzzle, an interesting detective—stop reading right now and go look up the book. Because from now on, I'm giving you my uncertainties about it.

Because Cleverly set the book in 1922 and, according to the jacket copy, spent her working life in  Cambridge and Suffolk, she is writing from the outside. That is, the book is based on extensive and, I'm convinced, careful research. But it does not have, cannot have, the easy air of authority that an author writing about her own time and inside her own experience can bring to the text. My complaint is not that the author does not know India (what do I know about India? not much), but that there is a thinness to the book because it is based on research.

Also, I personally have trouble accepting serial killers who are clever enough to get away with one murder after another until finally the right detective comes along to put all the pieces together. Cleverly tries to give her killer a background that will explain (justify?) the person's actions, but I am afraid that at the end, I was unsatisfied.

Finally, she took an interesting risk to write entirely from a man's point of view and while I had no trouble with Joe while I was reading The Last Kashmiri Rose, when I thought about the book later, I was not satisfied. I was not convinced that Joe would have had the kind of sexual relationship with the niece that Cleverly depicts. This may be an entirely personal idiosyncrasy and failing, so feel free to discount it.

Still, as I said in my first sentence, this is a very creditable debut mystery, and I expect that with time, Cleverly's stories became richer and more engaging.