East Berlin

On 29 March 1974, 38-year-old Kukuczka, a firefighter, entered the Polish embassy on East Berlin's Unter den Linden boulevard with a briefcase.

Erpenbeck, 57, was born and raised in East Berlin, which was part of East Germany until the country disappeared with German reunification in 1990.

Their novel Kairos follows the destructive love affair between a 19-year-old student and a married man in his 50s who meet on a bus in East Berlin around 1986.

But according to prosecutors, while working for the Stasi, he allegedly shot Czeslaw Kukuczka in the back from as he tried to cross from East Berlin to the West.

In 1974 he left Poland, ostensibly to spend the weekend in East Berlin.