Papa La-Bas by John Dickson Carr was published in 1969. The setting is 1858 New Orleans, it’s an unstable time as people can feel the probability of civil war in the near future. The story involves voodoo which is apparently called Papa La-Bas in New Orleans and isn’t always a force for evil, it can be used for good too.
There’s murder, romance, American southern gentility and for me it didn’t half drag, but I struggled on to the end, probably because there was a likeable Scotsman in it. As I recall John Dickson Carr was of Scottish extraction.
I did have a bit of a laugh at one point though as a character says: “I won’t ask about the state of the banking business. I won’t even ask whether any widows and orphans have been swindled today.” So nothing changes.
I’d read a couple of his historical mysteries before this one and quite enjoyed them, but for me the best thing about this book was the cover, I like the look of those US paddle steamers. I blame Mark Twain!