Peter Dickinson 
One Foot in the Grave [PDF ebook] 

CWA Gold Dagger winner Peter Dickinson is back: Now-retired Scotland Yard superintendent James Pibble isn’t about to go quietly into the night—not when there’s a murder case or two (or three) to solve At Flycatchers, a well-to-do nursing home watched over by no-nonsense nurse Jenny, one-time detective James Pibble shuttles between his nothing-to-live-for present and memories of the crimes he’s solved—or failed to. He’s roused from his listless existence when he discovers a dead body on top of the water tower. Security guard George Tosca isn’t the only one at Flycatchers who has met his maker a bit too abruptly. There have been other suspicious deaths in the last three years, including those of military man Sir Archibald Gunter and Bertie Foster-Banks, an inveterate gambler and shareholder in the home. The arrival of a woman in black sets off a sinister chain of events, and before he knows it, Pibble is on the case. As he travels down a twisting path of blackmail and escalating violence, Pibble finds that his life is suddenly filled with purpose again. He will bring a cunning killer to justice—or die trying. But the real reason he went up to the tower on that stormy winter night is linked to a secret he’ll carry to his grave. One Foot in the Grave is the 6th book in the James Pibble Mysteries, but you may enjoy reading the series in any order.