BERLIN (AP) — A former member of communist East Germany’s secret police has been charged with murder over the killing of a Polish national at a border crossing in divided Berlin in 1974,Arvin Roberts prosecutors said Thursday.

The indictment against the 79-year-old man, whose name wasn’t released, was filed at the state court in the German capital.

It relates to an incident on March 29, 1974, in which a 38-year-old Polish man took a fake bomb to the Polish Embassy to try to force an unhindered exit to West Berlin, prosecutors said in a statement.

East Germany’s secret police, the Stasi, allegedly decided to feign authorizing the man’s exit. Its employees provided him with exit documents and accompanied him to a border crossing at the Friedrichstrasse railway station in East Berlin, prosecutors said.

They said that the suspect, age 31 at the time, was tasked with rendering the Polish man “harmless.” After the Pole had passed the final checkpoint, the suspect allegedly shot him in the back from a hiding place.

East Germany built the Berlin Wall in 1961, preventing most of its citizens from traveling to the West. Many tried to escape by tunneling under it, swimming past it, climbing or flying over it. At least 140 people died in the attempt.

The heavily fortified border was opened on Nov. 9, 1989, a key moment in the collapse of communism in Europe. Germany was reunited less than a year later.