BERLIN — It was called “the shot that changed the republic.”
The killing in 1967 of an unarmed demonstrator by a police officer in West Berlin set off a left-wing protest movement and put conservative West Germany on course to evolve into the progressive country it has become today.
Now a discovery in the archives of the East German secret police, known as the Stasi, has upended Germany’s perception of its postwar history. The killer, Karl-Heinz Kurras, though working for the West Berlin police, was at the time also acting as a Stasi spy for East Germany.
It is as if the shooting deaths of four students at Kent State University by the Ohio National Guard had been committed by an undercover K.G.B. officer, though the reverberations in Germany seemed to have run deeper.
“It makes a hell of a difference whether John F. Kennedy was killed by just a loose cannon running around or a Secret Service agent working for the East,” said Stefan Aust, the former editor in chief of the weekly newsmagazine Der Spiegel. “I would never, never, ever have thought that this could be true.”
The revelation last week that researchers, looking into Berlin Wall deaths and East German intelligence, had stumbled across Mr. Kurras’s Stasi files raised a host of uncomfortable issues that are suddenly the subject of national debate.
For the left, Mr. Kurras’s true allegiance strikes at the underpinnings of the 1968 protest movement in Germany. The killing provided the clear-cut rationale for the movement’s opposition to what its members saw as a violent, unjust state, when in fact the supposed fascist villain of leftist lore was himself a committed socialist.
There is the sobering reminder of the Stasi infiltration of West German structures, but also the question of whether it went much deeper than has ever been uncovered. The Stasi’s reach in East Germany is well known; Chancellor Angela Merkel said just last week that the security service had tried to recruit her, though she had turned it down.