In 1991, Bakley became interested in Christian Brando. Christian, the eldest son of Academy Award-winning actor Marlon Brando and actress Anna Kashfi, became a media fixture when he was tried for the murder of his half sister's boyfriend Dag Drollet. Brando pleaded guilty to the lesser charge of voluntary manslaughter and was sentenced to ten years in prison. While he was in prison, Bakley began writing him and sending photos. After his release in 1996, Brando and Bakley began a romantic relationship. In 1999, Bakley discovered she was pregnant and initially thought that Brando was the child's father. In June 2000, she gave birth to her fourth child, a daughter she named Christian Shannon Brando.
While Bakley was involved with Christian Brando, she was also dating actor Robert Blake whom she met at a jazz club in 1999. After the birth of daughter Christian Shannon Brando, Bakley told Blake that she was unsure of the child's paternity and that he might be the father of the child. Blake insisted on a paternity test which later determined that Blake, not Brando, was the father of Bakley's youngest child. After paternity was established, the child's name was legally changed to Rose Lenore Sophia Blake.
Robert Blake and his defense attorneys claimed that Christian Brando was involved in the 2001 murder of Blake's 44-year-old wife Bonnie Lee Bakley. Robert Blake was ultimately charged with his wife's murder and although acquitted in the criminal trial, he was found liable for her death in the civil case.
Testimony introduced during the criminal pre-trial hearings and the subsequent civil trial attempted to implicate Christian in the murder, suggesting that he had the same motive as Blake to have Bonnie Lee Bakley killed. Bakley had become pregnant and claimed to both Brando and Blake that they were the father. A DNA test subsequently determined that Robert Blake, not Christian Brando, was the biological father.
According to trial testimony, just days before her death Bakley continued to claim Brando was the father of her child. Dianne Mattson testified in court that Brando became enraged, and at one point stated "somebody should put a bullet in that bitch's head". In a tape-recorded conversation between Brando and Bakley, Brando stated, "You’re lucky. You know, I mean, not on my behalf, but you’re lucky someone ain’t out there to put a bullet in your head.”
According to pre-trial testimony and corroboration, Christian Brando was in Washington state on the night of Bakley's death. Other pre-trial testimony alleged that associates of Brando were involved in the murder. One of those allegedly involved was the prosecution star witness: Duffy Hambleton, a stunt man. Hambleton claimed that Blake tried to hire him to kill Bakley. Hambleton claimed he refused the offer. Blake, however, testified that he hired Hambleton for personal security to protect himself and Bakley from a stalker. Criminal pre-trial and civil trial testimony claimed that Hambleton was an associate of Christian Brando and that he arranged the murder of Bakley to curry favor with Brando. The judge in the criminal case prevented the defense from presenting that view during trial.
Brando was called as a witness in actor Robert Blake’s civil trial but refused to testify, invoking his Fifth Amendment constitutional rights.[18] Brando's behavior in court got him a contempt of court charge and conviction.