The Federal Prosecutor's Office in Karlsruhe revealed that genetic material unmistakably belonging to Becker had been found on several envelopes of letters claiming responsibility for the attack on April 7, 1977.

The assassination of Siegfried Buback, a strong opponent of the left-wing extremist terrorist group, marked the beginning of a wave of terrorist acts by the RAF in their radical opposition to the West German government. It remained one of the highest-profile political killings carried out by the RAF throughout the militant group's campaign.

Buback, his driver Wolfgang Goebel, and Georg Wurster, a court officer, were all shot dead on the way to the court house in Karlsruhe. A motorcycle pulled up to Buback's Mercedes when it stopped at a traffic light, and a passenger on the back opened fire with an automatic weapon.

Eyewitnesses claimed the shooter had a slight build, suggesting a female assailant. Investigators, however, focused on RAF member Stefan Wisniewski, who ex-terrorist Peter-Juergen Boock had implicated as the possible shooter.

The Federal Prosecutor's Office said Thursday that while the discovery of Becker's DNA on the envelopes meant that she could not be ruled out as the assassin, it was not conclusive evidence in itself. Further investigations would follow.

New twist in on-going investigation

The new revelations come only a year after DNA testing on a motorcycle glove, helmet and jacket found after Buback's death had ruled out any connection to Becker, who was released from jail some 20 years ago after serving several years for RAF-related crimes.

Former RAF members Christian Klar, Knut Folkerts, Guenter Sonnenberg and Brigitte Mohnhaupt were convicted collectively of the Buback murder, but authorities remain unsure of who fired the deadly shots. Michael Buback, the son of the murdered prosecutor, had repeatedly named Verena Becker as a possible suspect.

"I am relieved that the efforts to clarify the details of the Karlsruhe assassination have been resumed," Michael Buback told reporters.

nda/dpa/AFP/AP
Editor: Nancy Isenson