As it turned out, the title was too long to fit on a Black Horse Western and so the final title is The Devil's Marshal. Anyhow, it's my 28th BHW and it's now available from all good libraries (well, the three or four left that Davy boy hasn't shut down).
In a travesty of justice, bounty hunter Brodie Latimer's sister Lucinda is found guilty of murder. Thwarted, when a witness is killed, but convinced of her innocence, he vows to find the real killer and, as more of Hamilton's leading figures die in mysterious circumstances, the clues lead him to Derrick Shelby, a man known as the Devil's marshal.
The only trouble is, Derrick died a year ago. How can Brodie clear his sister's name and bring the guilty to justice when the killer appears to be the spectre of a long dead lawman?