Verena Becker's house is located behind an Art Nouveau villa on a cobblestone street lined with street lamps from the turn of the 20th century. A practitioner of alternative medicine, Becker was once a member of the Red Army Faction (RAF), a far-left group that spread fear and terror throughout Germany more than 30 years ago. She has been living in a bungalow in the garden of the villa, which is owned by her sister, in Berlin's upmarket Zehlendorf neighborhood for many years.

But she cannot escape her past, even in this relatively hidden spot. Beginning this fall, the former terrorist will probably have to leave her comfortable, idyllic surroundings twice a week to travel to Stuttgart, where she will stand trial. The higher regional court in Stuttgart is expected to send the indictment, presented by the federal prosecutor's office, to Becker's attorney in Berlin this week.

There is no statute of limitations on murder. Federal prosecutors accuse Becker, a 57-year-old early retiree who lives on welfare, of being an accomplice in the assassination of Attorney General Siegfried Buback,  who was killed along with his driver Wolfgang Göbel and the head of the chauffeur service, Georg Wurster, in the southwestern city of Karlsruhe in the spring of 1977.

Unanswered Questions

More than 30 years after the murder, prosecutors are determined to find out who was responsible for one of the RAF's most spectacular attacks. Who fired the deadly shots into Buback's car from a motorcycle, who was driving the motorcycle and who was driving the waiting getaway car? These questions have remained unanswered, partly because most of the former RAF members have remained persistently silent on the matter to this day.

But does the federal prosecutor's office have enough evidence to convict Becker of being an accomplice in the murder?

The former terrorist was arrested last summer after a search of her house, in which investigators confiscated suspicious notes and a computer.  In December, however, Germany's Federal Court of Justice accepted an objection which Becker, who is chronically ill, had filed against the arrest. The court argued that there was too little evidence to prove that she had been an accomplice.

The federal prosecutors have been under a great deal of pressure since then. They cannot be certain that the judges on the Sixth Criminal Court in Stuttgart, which hears criminal cases involving national security, will support them, as was commonly the case during the years of RAF terror. The Stuttgart judges first want to give Becker's attorney the opportunity to state his case, and only then will they decide whether to allow the charges of being an accessory to murder, which could result in a life sentence. They could also -- in keeping with the decision by the Federal Court of Justice -- only allow prosecutors to charge Becker with aiding and abetting, which could involve a significantly smaller penalty.

Circumstantial Evidence

Given the lack of direct evidence, federal public prosecutor Walter Hemberger, who is in charge of the investigation, has collected circumstantial evidence -- including some items that the defendant contributed herself. For instance, on the 31st anniversary of the Buback assassination, Becker wrote, in one of the notes that were later found by investigators: "No, I don't know how I can pray for Mr. Buback. I have no real feeling of guilt and regret. Of course, I wouldn't do it again today, but isn't it pathetic to think and feel this way?!"

In another of Becker's notes, which also raises red flags for Hemberger, she writes: "What do I want to achieve? To clear S. (and others). To say what really happened."

Is "S." a reference to her former accomplice, Stefan Wisniewski, whom the federal prosecutors are also investigating in relation to the Buback case? Even during 117 days of pretrial detention last year, Becker did not make any statements. In a recorded telephone conversation with Brigitte Mohnhaupt, a former leader of the RAF, Becker said that she did not believe "that they can do anything, except to say: Well, there are the letters claiming responsibility…"

According to DNA analysis performed by the Federal Criminal Police Office (BKA), Becker sealed the three envelopes that contained the letters claiming responsibility for the murders of Buback and the others. The envelopes are the only new pieces of evidence of Becker's involvement in the Buback murder, despite the great lengths taken by forensic experts to come up with evidence against Becker. For example, they also tried to find traces of Becker's DNA on the trigger of the murder weapon, a Heckler & Koch semi-automatic rifle, but were unsuccessful.

Who Pulled the Trigger?

The only undisputed part of the case is the following facts: At shortly after 9 a.m. on April 7, 1977, in Karlsruhe, two members of the RAF approached Buback's official car on a Suzuki motorcycle. The person sitting on the motorcycle's rear seat fired at least 15 shots into the Mercedes. The duo on the motorcycle escaped in a waiting car driven by an accomplice.

Former RAF member Knut Folkers was sentenced to life for the Buback assassination, in which prosecutors argued he was either the shooter or the driver of the motorcycle, but he has since submitted a relatively believable alibi. Two other members of the terrorist group, Christian Klar and Brigitte Mohnhaupt, also received life sentences, partly because of the Karlsruhe murders. In its grounds for Klar's conviction, the court argued that he "was either the driver or passenger on the motorcycle, or was waiting in the Alfa Romeo." Mohnhaupt was convicted because, according to the judges, she had played "a key role" in the "planning and preparation" of the assassination.

The federal prosecutor's office did not, however, bring charges against Verena Becker and Günter Sonnenberg, even though they had the murder weapon in their possession when they were arrested four weeks after the Karlsruhe assassination. Becker was only convicted for a shooting incident that happened before her arrest in May 1977, in which two police officers were wounded.

The federal prosecutors also spared Wisniewski in their investigations of the Buback killing, despite the fact that, according to two dossiers compiled by the German domestic intelligence agency, the Federal Office for the Protection of the Constitution (BfV), Sonnenberg had driven the motorcycle, Wisniewski fired the gun and Klar drove the getaway car.

'Absurd and Distressing'

Michael Buback, the son of the former attorney general, calls the problematic legal treatment of the case "absurd and distressing." "It's very likely that none of the three people who were convicted of murdering my father were sitting on that motorcycle," says Buback, who is a professor of chemistry in the central German city of Göttingen. Both Buback and his mother are joint plaintiffs in the trial.

Buback is particularly critical of the actions of his father's successor, former Attorney General Kurt Rebmann, which he calls "outrageous." The BfV had provided Rebmann with a 227-page "operations memorandum" from December 1981 and an 82-page "evaluation memorandum" from March 1982. Both documents were based on conversations between BfV officials and Becker while she was in prison.

Becker had broken down under the harsh conditions in prison and hoped to receive a shorter sentence in return for providing confidential testimony. She succeeded in her wish. When Becker, with Rebmann's support, was pardoned by then-German President Richard von Weizsäcker in 1989, she had only served about nine years of her sentence for attempted murder of a police officer. It was the shortest amount of time served out of all the RAF members sentenced to life in prison.

Instead of launching investigations against Wisniewski and Sonnenberg, who were heavily incriminated by Becker's statements, Attorney General Rebmann did nothing. It is also likely that he later took steps to ensure that the incriminating dossiers disappeared without a trace in Karlsruhe. SPIEGEL revealed the existence  of the secret documents in April 2007. Four weeks ago, Interior Minister Thomas de Maizière had them turned over to federal prosecutors for use in court. His predecessor, Wolfgang Schäuble, had refused to release the documents for almost two years.

Protecting Their Source

The absurd thing about the mysterious dossiers is the attempt by BfV agents to protect their valuable source. The name Verena Becker, on whose testimony the documents are based, doesn't appear in the dossiers. Meanwhile, Becker's attorney categorically denies that she was the source.

Michael Buback firmly believes that Becker was the one who fired the gun in Karlsruhe. "I know of 10 witnesses," says the chemistry professor, "who saw a small, petite person, in other words a woman, sitting on the back of the motorcycle." Buback says he is "99 percent certain that Sonnenberg was driving the motorcycle and Becker was sitting on the back."

"This can't be taken seriously anymore," says Walter Venedey, Becker's defense attorney. He insists that such recollections can no longer be considered reliable after 30 years. "And the federal prosecutor's office also doesn't agree with Buback in this respect," he says.

Given the absence of evidence proving that Becker was directly involved in the murder, federal prosecutor Walter Hemberger tried to determine what her role was in the preparations. According to former terrorist Peter-Jürgen Boock, she attended two RAF meetings, one in Germany's Harz Mountains and one in the Netherlands. At the time, the group voted unanimously to conduct a "punitive operation" against Buback.

'Proletarian Mystique'

One former RAF member says that Becker was a "dyed-in-the-wool member" who cultivated a "proletarian mystique." The ex-member also claims that Becker served as the de facto "leader of the RAF" from the end of 1976 until Brigitte Mohnhaupt was released from prison in late February 1977.

But the federal prosecutors will have trouble proving Becker's position in the group in court. Boock is the only former RAF member who has not refused to testify in the context of the investigations. And Boock, long a drug addict, is seen by more than just one former federal prosecutor as someone who likes to make up stories. One source ironically described him as the "Karl May of the RAF," in a reference to the German author who wrote Wild West novels without ever having visited the US.