‘How many more? San Francisco jury finds man guilty of 1978 rape/murder, putting spotlight on possible crimes across three states
A man who raped and strangled to death a 15-year-old girl visiting San Francisco more than 47 years ago was found guilty of first-degree murder this afternoon by a jury at the city’s Hall of Justice.
Mark Personette, 80, took Marissa Harvey to Sutro Heights Park where he sexually assaulted and killed her. The girl left her sister’s house on the morning of March 27 1978, to go riding in Golden Gate Park, but did not return. Her remains were found the next day in deep undergrowth; her clothes had been removed and then replaced and her underwear was missing.
The jury of five men and seven women returned a unanimous verdict after scarcely four hours’ deliberation.
Personette will be sentenced on December 17 2025. While the trial marks the end of a nearly fifty-year search for Marissa’s killer, it leaves authorities in California, New Jersey and Colorado under pressure to account for other cases in which Personette may be implicated.
It emerged that Personette kept mementos of his crime in a battered suitcase stored in his home and that he remained ready to commit more murders by keeping in each of his cars ropes, knotted at each end, of an identical width and knot pattern to the ligature used to choke to death Marissa Harvey.
“A pedophile, a rapist, a murderer,” prosecutor Katherine Wells told the jury of the defendant in her closing argument. “Every single thing you’ve seen and heard in this courtroom went to the conclusion that Mark Personette took Marissa Harvey’s life. That Mark Personette was the one who put a rope over her neck, knotted it, and he was there when she gasped for her very last breath.”
“That he watched as he pulled on that rope as she lost consciousness, as her body went limp, and continued holding steady on that rope for minutes more until she died.”
Prosecutors believe Marissa crossed paths with Personette as she tried to return to her sister’s house from the stables at Golden Gate Park and that the attack was likely a crime of opportunity.
Personette lived in the Bay Area at the time of the attack, working at Mare Island shipyard near Vallejo. He moved to New Jersey shortly after Marissa’s murder.
“Don’t give that man your sympathy, he doesn’t deserve it. He wasn’t always old, he wasn’t always hard of hearing, he wasn’t always in a wheelchair. He was a young man, a strong man, a conniving man, a vicious, violent, sadistic man.”
Prosecutor Katherine Wells
The court heard compelling testimony from a woman who said she, as a 16-year-old, was attacked by Personette in New Jersey a year and a half after Marissa’s death.
He had picked her up while she was hitchhiking, she said, but instead of driving her home, took her to a remote wood where he beat and raped her. He was acquitted at trial.
While she gave evidence, Personette, sitting some fifteen feet away, angled himself in his chair to peer directly at the now middle-aged woman.
Prosecutors drew comparisons between this attack and the one in which Marissa was murdered. Each was conducted in a secluded heavily-wooded area, in each the victim’s clothes were quickly removed – shown by the pristine state of Marissa’s t-shirt when she was found – and the New Jersey victim was raped face-down and Marissa was ultimately killed from behind, with the ligature wrapped around her neck and pulled tight from the back.
“[She] is the living echo of Marissa,” Wells would later say. “The exact same age as Marissa. Had Marissa been able to come and testify about what happened to her she would be [her] age. That’s how much life she has missed out on. That’s how much life he has taken from her.”
Prosecutors ultimately did not field other potential witnesses who claimed they were harmed by Personette. A second woman said she fought off an attempted abduction by him in New Jersey at around the same time as the rape – an attack for which he was also acquitted. Another woman came forward after Personette’s mugshot was released, saying she fought off what bore the hallmarks of an attempted abduction in Golden Gate Park at around the time of Marissa’s murder.
The jury did not learn about Personette’s New Jersey convictions for indecent exposure and being drunk and disorderly.
Forensic genealogy provided the key to unlocking the case. Investigators uploaded the suspect’s DNA profile, obtained from samples found on the victim’s clothes, to a genealogy website. They developed a family tree of those related to that person and ultimately honed in on the suspect.
Much of the detail of that part of the investigation was kept from the jury who were told simply that a “lead” led police to Personette.
Two FBI special agents, John Childress and Joseph Gonzalez, gave evidence about the surveillance operation set up in May 2021 to monitor Personette in rural Colorado.
It took six months, they said, before they were able to retrieve a sample of their target’s DNA which investigators in San Francisco could then use to definitively compare with DNA at the crime scene.
They succeeded on October 8 2021 after following Personette to a Walmart Supercenter 17 miles from his home. There he took trash from his car and deposited it in two separate trash cans: one in the main lot at the front of the store, and another next to a tire shop at the side of the store.
They were surprised to learn that this did not include ‘normal’ trash, but rather material of potential forensic value, dental floss, cotton swabs, tissues, and even a plastic milk jug containing urine. It was from this bottle that a sample of DNA was recovered and matched to that found on Marissa Harvey.
“If you happen to be somebody who ejaculated into and killed a 15-year-old-girl in 1978, totally unaware of the idea of DNA,” said Wells, “and then in 2018, 2019, 2020 you start seeing big national news that the Golden State Killer…was caught because he left a tissue in his garbage can and the FBI picked it up, you might start worrying about that. You might start changing your behavior.”
“This is all consciousness of guilt,” she added.
During a subsequent search of Personette’s home the FBI found mementos of his time in the city, including an old suitcase in which was found a 1970s map of San Francisco and women’s underwear.
Two California license plates, with registration tags indicating use at the time of the murder, were found, as were two knotted ropes, kept in separate vehicles, which investigators say were the same width as the ligature used to strangle Marissa.
Jurors were not told about either the underwear or the ropes.
“Her injuries certainly suggest that she put up a huge fight against the defendant.”
Prosecutor Katherine Wells
Wells conceded that prosecutors did not know everything about the crime.
“Marissa cannot speak from the grave,” said Wells. “We’ll never know exactly how she spent those final moments. Was she crying like [his other victim]? Was she begging for him to stop? Was she punched with the force of a baseball bat? Was she threatened? Did he make her tell him that she liked it?”
“There are so many things that we can’t know about what happened to her. And one of those things is why he killed Marissa and let [the other victim] live?”
“Did Marissa yell too loud? Did someone walk past too closely? Did she fight too hard? Did she make it too inconvenient to rape her, so he killed her?”
“Her injuries certainly suggest that she put up a huge fight against the defendant.”
Wells attacked the defense approach of tacitly conceding Personette’s DNA was found in and on Marrisa’s body and clothes.
“The defense wants you to believe that it is reasonable that somebody else committed this crime – that somebody else killed Marissa,” said Wells.
“She was the most unlucky girl in San Francisco that day,” scoffed Wells, “That after Mark Personette brutally raped her leaving her bleeding…a second monster came to that exact location prepared with a rope and killed her.”
“They’ll have you believe that this second monster, for no reason at all, just decided to help Mark Personette out and take care of his witness problem for him – to get rid of the living witness to his awful brutal crimes against a teenage girl who was visiting our city.”
“Who killed a 15-year-old whose body was dumped in the bushes?” Wells asked. “The guy whose DNA was all over her. That’s who did it and we know who that guy is, we know we have one perpetrator, and there is on crime scene, one rapist, one DNA profile. And that person is Mark Personette.”
She dismissed a DNA result which showed another DNA profile as laboratory contamination.
“Don’t give that man your sympathy,” said Wells, pointing to Personette, “he doesn’t deserve it.”
“He wasn’t always old, he wasn’t always hard of hearing, he wasn’t always in a wheelchair. He was a young man, a strong man, a conniving man, a vicious, violent, sadistic man. Convict that man the same way that you would convict him,” she concluded pointing to a mugshot of Personette in 1979.
The defense fielded a single witness – DNA expert Gary Harmor – who sought to bolster their case that there was more than one assailant of Marissa and, as such, it could only be said with certainty that Personette raped Marissa and it could not be said with confidence that he murdered her.
But while he testified that a second DNA profile was recovered from the crime scene, which he said was evidence of a second assailant, he conceded during cross examination that lab contamination made more sense as an explanation for its presence.
“If there are multiple possible perpetrators and you don’t know who committed the homicide you can’t convict someone because you are angry,” maintained defense attorney Adam Gasner in his closing.
“I am not required to prove who did it. They – the D.A.’s office – are required to prove beyond a reasonable doubt that Me Personette committed the homicide.”
“There is zero – let me repeat, zero – hard evidence…besides the DNA relating to a possible sexual assault, that connects Mr Personette to a homicide.”
This afternoon in Department 10 of San Francisco’s Hall of Justice, Personette appeared unmoved as the clerk announced the verdict.
Sat in his wheelchair, he stared straight ahead, ignoring the jury who had deliberated for just under four hours over two days.
Judge Michael Rhoads set sentencing for December 17 2025.
A concern that this murder represented the tip of a much deeper iceberg loomed over the trial. Before opening statements, lawyers fought over whether jurors would hear about the two knotted ropes Personette kept in his cars — details whose implication was clear: he seemed ready to kill any girl he came across.
Personette’s memento-keeping behavior – including a 1970s map of San Francisco found in a suitcase with women’s underwear against a backdrop were Marissa’s map and underwear were never found – and the extreme lengths to which he went to conceal his forensic footprint are also plainly worrying.
Indeed San Francisco Police Department raised the prospect on Personette’s arrest, asking law enforcement across the nation to review their unsolved cases to see if he may be the culprit.
A spokesman for Jefferson County Sheriff’s Department would not be drawn on whether they had probed Personette’s potential involvement in other local crimes, simply stating that this was not their case or their investigation. This incurious approach may surprise at least one of his former neighbors in Conifer, CO who worried about him and would not let his daughter or their friends near his home.
San Francisco Police Department and the San Francisco field office of the Federal Bureau of Investigation have been approached for comment.
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