Automatically Dead: Ron Webb Mystery number 9.

Automatically Dead by Pete Jennings.
DCI Ron Webb has a baffling case in Lavenham when a collector of automatons is found strangled in a room locked from the inside. Was it an interrupted robbery gone wrong, a disgruntled business partner, his wife, or his niece who was responsible? What role did the valuable collection of elaborate mechanical marvels play? Together with DS Peggy Catchpole and the rest of his small team, the puzzle must be solved.
Number 9 in the Ron Webb Mystery series.