The Drowned Man — David Whellams

A retired Scotland Yard detective is lured back to work in “a series to follow particularly for Louise Penny fans and the Masterpiece Mystery set” (Library Journal).
 
Chief Insp. Peter Cammon is supposed to be retired, but he's reluctantly agreed to travel to Canada to retrieve the body of a murdered colleague. And once he's involved, he can't resist delving into the oddities of the crime.
 
His fellow cop was brutally attacked, run over by a car, and then dumped into a canal -- all seemingly linked to the theft of three letters from the American Civil War era, one of which may have been signed by John Wilkes Booth . . .
 
“Tightly plotted and featuring a lead character who keeps us glued to the page, the book should definitely suit readers looking for an intriguing lead character and a solid mystery.” -- Booklist