Just finished reading "The Breath of God", and I enjoyed it a lot... and yet one point puzzles me. Why did you choose to explain the first death so vaguely? Were you simply unable to come up with a detailed solution?
Glad you enjoyed the book!
As for the explanations, I'm sorry you thought it too vague. The explanation for the first death was actually quite simple though, the Breath of God killed him.
My method with the entire resolution was to trim as much of the explanatory dialogue as possible. As a reader you need those moments but there's always a risk they'll go on too long and throw the pacing for what was always intended to be an action-orientated climax. So, I cut everything I felt was unnecessary leaving just enough to cover all the facts. Obviously, for you, it wasn't quite enough! Which is a perfectly fair point.
I was also trying to balance the importance of Holmes remaining a rationalist with the supernatural elements of the book. The theme was about belief in the end, if you believe in magic the battle's half lost. That's why the Breath of God was able to make such a mess of De Montfort (the first murder) but Holmes was able to stand against it.
