In May 1945, British soldiers near the Austrian border town of Klagenfurt handed over 26,000 Yugoslav anti-Communist refugees to Tito's Communist partisans, who disarmed then machine-gunned them. Who was responsible? Timewatch has investigated the records and, for the first time, British officers and Yugoslav survivors describe what happened. In 1348, the Black Death killed one in three of the population. Until now we have always assumed it was an outbreak of bubonic plague. Now a zoologist suggests a far more fearsome disease was the cause. Christopher Andrew investigates.