File photo - Defendant Verena Becker, a former member of the "anti-imperialist" Red Army Faction.

Stuttgart - A German court on Friday sentenced a 59-year-old former left-wing terrorist to four years in jail for her role in the assassination in April 1977 of the nation's chief prosecutor, Siegfried Buback.

The court's conviction of Verena Becker helped to shed some light on one of the most notorious and puzzling murders carried out by the 1970's terrorist group, the Red Army Faction (RAF), which was involved in more than 30 killings throughout the country. This included the drivers and officials accompanying the RAF's targets.

Three members of the militant left-wing group were previously charged with Buback's murder.

But in handing down its decision Friday, the court in Stuttgart was still unable to say who actually fired the shot that killed Buback, a former member of the Nazi Party and an outspoken critic of the RAF.

Friday's court decision represented a small victory for Buback's son Michael, who has campaigned for years for an exclamation of the events surrounding his father's death.

The Berlin-born Becker, who was a member of the left-wing militant group at the height of its terror campaign against the German establishment during the 1970's, was sentenced to life imprisonment in late 1977 for her involvement in a criminal organisation.

She was released in 1989 following a pardon from the German president and later changed her name and lived anonymously.

However, Becker was arrested again in August 2009 on charges of being involved in the Buback killing after new DNA evidence linking her to the crime and witnesses claimed that a woman might have been on the motorcycle used in the attack.

In sentencing Becker, the court noted that she had already served two and half years because of previous conviction.

The RAF, which emerged from the radical student movement of the late 1960's, finally disbanded itself in 1998.

Becker, who had denied involvement in the murder of the former chief prosecutor, had previously claimed that another RAF member, Stefan Wisniewski, had been the one that killed Buback.

Michael Buback had claimed that it was Becker who fired the shot that killed his father as he travelled in car to the court in the west Germany city of Karlsruhe. However, the court could not find any evidence of this.

Buback's death set the stage for a period of violence in Germany, which became known as the German Autumn, and which included the kidnapping and assassination of the head of the nation's employers federation and the hijacking of a Lufthansa jet by the Popular Front for the Liberation of Palestine. - Sapa-dpa