After a two-week break, Iain is back in the driving seat this week. His case takes place in St. Louis, Missouri, during the 1930s. When William Kappen is found dead on the day he is due to get married, police are immediately suspicious of his estranged sister Marie. Find out how a patch of poison ivy helps break open the case and lead investigators to track down William’s killer – or killers, should we say.Murder They Wrote with Laura Whitmore and Iain Stirling is available weekly on BBC Sounds. Subscribe now so you never miss an episode. Email us at [email protected].