In the summer of 1984 three teenage girls from Placerville, a town in El Dorado County in the Sierra Nevada foothills of California, died within about two months of one another. They were Denise Galston, Lynda Burrill and Debbie Galston. Denise and Debbie were 14-year-old sisters; Lynda was 18.
Michael Anthony Cox, who was 27 in 1984, was arrested on November 10, 1984, and in 1985 a jury in El Dorado County found him guilty of three first degree murders and found true the special circumstance of multiple murder. On November 26, 1985, he was sentenced to death. The California Supreme Court affirmed the judgment on June 9, 2003, and rejected a separate petition for a writ of habeas corpus the same day. A federal habeas corpus petition followed in 2004. In November 2026 the Governor of California announced that he intended to replace every death sentence in the state with life imprisonment without the possibility of parole.
Cox was 27 in 1984. He lived and worked in Placerville. He met a young woman in January 1984, and they married on September 15, 1984. He left the marriage in November 1984, the month he was arrested.
The trial record contains a stipulation that he had no prior felony convictions. At the penalty stage his defense called a number of people from his working life, who described him as a dependable worker. His mother and half-sister gave evidence about a difficult childhood in which he helped to look after younger siblings. A psychiatrist told the jury that he had a history of alcohol abuse that was in remission, and that he had mild organic brain syndrome. A neuropsychologist who gave evidence for the defense found no brain damage, and the trial judge accepted that evidence.
Denise Galston was 14 and lived in Placerville with her sister Debbie. The California Supreme Court dates her death to June 12, 1984, the first of the three killings.
Lynda Burrill was 18 and lived in Placerville. She died in the summer of 1984, between the deaths of the two sisters; the exact date of her death is not on record.
Debbie Galston was 14 and the sister of Denise. She was the last of the three to die, in August 1984, nearly two months after her sister; the exact date of her death is not on record.
The inquiry spread across the summer and autumn of 1984. Detectives interviewed Cox on July 20. Further conversations with Cox and with the young woman he later married took place in August. The investigation turned on the evidence of a witness who had been away from Placerville and returned in late October 1984. She came forward to the sheriff's office and, between November 1 and November 7, met with sheriff's personnel and a psychologist. Cox was arrested on November 10, 1984, and charged with the three murders. About two weeks after the arrest, the young woman he had married told police of statements that she said he had made to her.
A preliminary hearing was held. Cox was represented at trial by two lawyers from one firm, which had at some earlier stage acted for several people who were prosecution witnesses. Cox waived any conflict on the record, and the California Supreme Court later found that there was no actual or potential conflict.
Cox was charged with three counts of first degree murder under Penal Code section 187, with the special circumstance of multiple murder under section 190.2, subdivision (a)(3). The case was tried in the El Dorado County Superior Court, where it was numbered 44625, before Judge Terrance M. Finney. Testimony began in early June 1985, and the trial lasted about a month. Ninety witnesses gave evidence.
The defense challenged a number of rulings made along the way. Questions put to witnesses were struck from the record on two occasions, and the jury was told to disregard them; the court held that those were not grounds for a mistrial. Evidence that two witnesses had been afraid of Cox was admitted, and statements made by a witness about directions she was given were admitted as evidence of her state of mind, with a limiting instruction.
The jury returned verdicts of guilty on all three counts and found the multiple-murder special circumstance true. At the penalty phase the prosecution presented no new evidence and relied on the circumstances of the three murders. The defense called the working-life witnesses, family members and the psychiatrist described above. Two former forestry crew members gave rebuttal evidence about his conduct toward women colleagues.
The jury fixed the penalty at death. On November 26, 1985, the judge, in ruling on the automatic motion to modify the verdict under Penal Code section 190.4, subdivision (e), found that the aggravating circumstances "overwhelmingly outweigh the mitigating factors," and sentenced Cox to death.
The appeal to the California Supreme Court was automatic under Penal Code section 1239, subdivision (b). The State Public Defender's office acted for Cox, and the Attorney General's office represented the State. Cox raised claims about conflicts of interest, about the questions put to witnesses, about the admission of certain evidence, about his absence while testimony was read back to the jury, and about cumulative error. The court rejected each. On the penalty phase, it held that the trial judge had made two errors in reviewing the verdict, one in treating the present crime as an aggravating factor and the other in describing the mere possession of an item as a crime of violence, but that both were harmless. It concluded that "No basis for a remand appears."
The decision was written by Justice Moreno and filed on June 9, 2003. The Chief Justice and Justices Baxter, Werdegar, Chin and Brown agreed with it. The disposition reads that "the judgment is affirmed." Justice Kennard dissented. She would have granted relief on the separate habeas corpus petition and dismissed the automatic appeal as moot.
That petition, In re Cox, had been filed on February 29, 1988, while the appeal was still pending. It alleged that several prosecution witnesses had testified falsely, that the prosecution had withheld a statement from a potential witness, and that trial counsel had not investigated adequately. The court issued an order to show cause on August 18, 1988, and in 1989 it directed that evidence be taken on those matters. Supplemental petitions in 1990 and 1994 added further claims of false testimony. A hearing before a referee, a retired San Joaquin County Superior Court judge, began in February 1994 and ended on January 19, 1995. His report, 1,129 pages long, was filed on July 7, 1999. He found that some of the testimony had been false but not substantially material, that the prosecution had received no relevant information from the potential witness, and that counsel's performance was deficient in some respects but not prejudicial.
The court accepted most of the referee's findings. Its disposition reads: "For the reasons stated below, we discharge the order to show cause." The dissent took a different view of the materiality of the false testimony and of the reliability of the account of one key witness.
On January 5, 2004, a federal habeas corpus petition under 28 U.S.C. section 2254 was filed in the United States District Court for the Eastern District of California, in Sacramento, under the title Cox v. Ylst. The case was handled by Magistrate Judge Carolyn K. Delaney. A scheduling order of July 9, 2014, set deadlines for the petitioner's briefing, and by an order of January 9, 2018, a non-party witness was authorized to be examined by deposition on February 8, 2018. No ruling on the petition is on record.
California's death penalty cases are reviewed in the state's highest court by automatic appeal, which is why the judgment against Cox went directly to the California Supreme Court. Separate habeas corpus petitions may be filed alongside that appeal, as occurred here, and federal habeas proceedings follow in the federal courts.
On November 5, 2026, Governor Gavin Newsom announced that he would use his clemency authority to replace the death sentences of the 548 people then under sentence of death in California, 529 men and 19 women, with life imprisonment without the possibility of parole. The California Constitution requires the California Supreme Court to approve clemency for a person convicted of a felony more than once, and the Governor's office said that the court would need to approve 382 of the commutations, about 70 percent. The change does not release anyone, does not make anyone eligible for parole, and does not alter the underlying convictions.
A list of intended clemency recipients published on the Governor's website in November 2026 includes the entry "Cox, Michael Anthony," with the corrections number D19400, El Dorado as the charging and trial county, the date 11/26/1985 and the case number 44625.
The habeas corpus proceedings tested the testimony of several prosecution witnesses. The referee found one witness's account of seeing events true but another part of her testimony false, and found that another witness's account of statements made to her had been fabricated under pressure. The California Supreme Court held that the false evidence was not substantially material and denied relief; Justice Kennard, in dissent, would have granted it.
The exact dates of death of Lynda Burrill and Debbie Galston are not on record.
June 12, 1984: Denise Galston dies.
Summer 1984: Lynda Burrill dies.
July 20, 1984: a detective interviews Cox.
August 1984: Debbie Galston dies.
September 15, 1984: Cox marries.
November 7, 1984: the witness completes her meetings with sheriff's personnel and a psychologist.
November 10, 1984: Cox is arrested.
June 1985: trial begins in El Dorado County.
November 26, 1985: Cox is sentenced to death.
February 29, 1988: habeas corpus petition filed in the California Supreme Court.
January 19, 1995: the referee's hearing ends.
July 7, 1999: the referee files his report.
June 9, 2003: the California Supreme Court affirms the judgment and discharges the order to show cause on the habeas petition.
January 5, 2004: federal habeas corpus petition filed.
January 9, 2018: a federal order authorizes a deposition.
November 5, 2026: the Governor announces intended clemency for all death sentences.