Lonely road murder

Rosemary Lennox is horrified to find her best friend and neighbour, Mary Francis, strangled in her flat and it's not long before her husband, John Francis, is also murdered there too. The police question Rosemary, her friend and fellow lodger Bob McDonnell and their landlady Ellen Moreland, but they are unable to establish a motive. However, when Rosemary and Bob attempt to investigate, she discovers that all the evidence points to her friend ...