Becker was detained at her Berlin home on Friday after incriminating material was found during a search of her apartment last week. A new investigation into Buback's shooting was launched last year based on DNA evidence.
According to the arrest warrant, Becker made "essential contributions to the preparation and execution of the attack." Two other men escorting Buback were also killed.
Becker's DNA was found on the envelope in which a letter claiming responsibility for the assassination was sent by the RAF. Such a discovery would not have been possible with the forensic technology available to investigators 32 years ago.
Other members of the now disbanded Red Army Faction (RAF) have already been convicted of the April 7, 1977 assassination, but a case against Becker was dropped in 1980 for lack of evidence. Prosecutors say they have no evidence directly linking Becker to the masked gunman who fired the shots at Buback's car from a motorcycle, but do have clear indication of her involvement in the killings.
Becker has already served a prison sentence for her role in other terrorist attacks, but she has been free since 1989. The RAF terrorized West Germany in the 1970s with a campaign of bombings and murder intended to inspire a "worker uprising" and create a hard-line communist state.
Editor: Rick Demarest