Humdrum mystery from 1957. Apart from the sinister hints about the murdered millionaire having had dealings behind the Iron Curtain and a remarkable absence of tea, this might have been set in the 1930s.
When Rufus Bader is found dead in his conservatory after dinner, murder has to be suspected- but the actual cause of death proves elusive. And who should Inspector McLean suspect? The absentee, much younger wife? The wayward niece, who had defied her uncle's wishes in becoming engaged to a penniless artist? And who is the mysterious Alwell, whose next of kin stands to benefit from the will?
The only original aspect of this by-the-numbers mystery was the murder method. I'm not sure it would stand up to modern forensic science, though.