Officials will collect DNA samples from Becker and compare them to DNA clues left at the crime scene, spokesperson Sonja Heine told broadcaster Südwestrundfunks on Friday.
"Suspicions have not changed over the last few months," Heine said.
In December the federal prosecutor's office revealed that it could not rule out the possibility of a female suspect linked to three clues - on a motorcycle helmet, motorcycle gloves, and a jacket left in the getaway vehicle. But Heine said that analysis using new forensic technology makes Becker a possibility at best and she might be ruled out entirely based on the evidence.
Buback, a strong opponent of the leftist terrorist outfit during his term, was killed along with his driver Wolfgang Göbel, and a judicial officer, Georg Wurster, on the way to the court house in Karlsruhe. A motorcycle pulled up to Buback's Mercedes at a stoplight, and a passenger on the back opened fire with an automatic weapon.
RAF members Christian Klar, Knut Folkerts, Günter Sonnenberg, Brigitte Mohnhaupt have all been convicted collectively of the crime, but authorities remain unsure of who fired the deadly shots. Michael Buback, the son of the murdered prosecutor has repeatedly named Verena Becker as a possible suspect, and said he welcomed the new investigation, news agency DDP reported.
"I think it's overdue," he said.
The federal prosecutor's office has also been investigating Stefan Wisniewski, after ex-terrorist Peter-Jürgen Boock recently implicated him as the possible shooter.
The head of the investigation at the Federal Court of Justice has threatened Mohnhaupt, Folkerts and Klar - who are no longer incarcerated - with jail time if they don't break their silence about the event. That decision is currently under review by the court.
Buback's murder was the first crime in a series of terrorist acts by the militant communist RAF group in their radical opposition to the West German government that came to be known as "German Autumn" in 1977.