They Do It with Mirrors - A Miss Marple Mystery

Miss Marple senses danger when she visits a friend living in Stoneygates, a rehabilitation center for delinquents. Her fears are confirmed when someone shoots at the administrator. Although he is not injured, a mysterious visitor is less fortunate - shot dead simultaneously in another part of the building. Pure coincidence? Miss Marple thinks not, and must use all her cunning to solve the riddle of the stranger's visit - and his murder.