A bungled bomb plot in Poland exposed a spy – but whose spy was he?

When exiled Russian opposition campaigner Igor Rogov was accused of working for the Kremlin, his friends were shocked. Could this young activist have really been an undercover agent? By Shaun Walker. Read by Kobna Holdbrook Smith. Additional reporting by Ada Petriczko. Help support our independent journalism at theguardian.com/longreadpod