They Do It With Mirrors Christie Agatha (2016)

A shocking crime takes place in a mansion filled with suspects. Ruth Van Rydock cannot shake the feeling that something terrible is going to happen to her sister at Stonygates, so her old school friend Jane Marple decides it is time to pay a visit. But this grand Victorian mansion is not just a family home; it is also a correctional facility for wayward young men. When something terrible does happen, Miss Marple must face her most eccentric cast of suspects yet.