Trial begins of man accused of 1978 rape and murder of girl in San Francisco
Story update: Personette was found guilty on November 12 2025.
The trial of the man accused of raping and strangling to death a 15-year-old girl visiting San Francisco began today, more than 47 years after the murder, with prosecutors telling jurors they had a conclusive DNA match tying the defendant to the crime and they had found incriminating evidence during a home search.
The court heard that Mark Personette beat, sexually abused and killed Marissa Harvey before dumping her body in Sutro Heights Park. The girl had left her sister’s house on the morning of March 27 1978, intending to go riding in Golden Gate Park, but did not return. Her remains were found the next day deep in undergrowth; her clothes had been removed and then replaced and her underwear was missing.
“She had a map with her, she wanted to look around and enjoy the city. Instead she met this man and he took her and he beat her and he raped her and he strangled her and he murdered her.”
Prosecutor Heather Trevisan
“She had a map with her, she wanted to look around and enjoy the city,” assistant district attorney Heather Trevisan told the jury of the victim, before turning to point at the defendant. “Instead she met this man and he took her and he beat her and he raped her and he strangled her and he murdered her.”
“And she never made it home,” she added.
The jury were shown images of the victim’s body taken by the medical examiner.
“There were leaves found inside of her pants and her underwear was missing,” said Trevisan.
“You’ll see the bruising and fingernail scratches at the back of her neck where she tried to get the ligature off. You’ll see the bruising and swelling to her face. She had significant injuries – she had been beaten. You’ll see the injuries to her arms where she had been struggling. Her earring was ripped out.”
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, were then able to hone in on the suspect himself.
Much of the detail of that part of the investigation will be kept from the jury after the district attorney’s office won an order barring its disclosure to the defense. This morning they were told simply that a “lead” led police to Personette.
Trevisan told the jury that in late 2021 the FBI was tasked with covertly obtaining a DNA sample from the defendant, who had been tracked to his home in Conifer, Colorado. This evidently proved something of a challenge.
“You’ll hear from three special agents from the FBI in Colorado who would try to find something discarded by Mr Personette,” she said.
“Finally they saw him drive many miles to a Walmart parking lot.”
“He got out of his car and he took a plastic bag and he walked over to a trash can and put it inside.”
“He went back for another bag, went over to a different trash can, and put it in.”
“So what exactly was in this bag?” Trevisan asked jurors while an image of one of the retrieved bags was displayed on a large TV monitor.
“Well it’s hard to see here…it’s hair. It’s dental floss, there are used Q-tips, there are used tissues and there was a bottle of urine.”
“What’s not in this trash was your usual garbage…food scraps or receipts. Anything of forensic value – blood, urine, anything – was hidden in this trash, driven miles away and dumped in different locations.”
Those items were retrieved, a sample of Personette’s DNA was obtained from the urine, and then compared with DNA found on Marissa’s clothes. The match, said prosecutors, was conclusive.
Jurors heard that police searching Personette’s home found mementos of his time in the city.
“They found this old suitcase hidden in a closet and, in that suitcase, they found a 1970s map of San Francisco. They also found a 1970s map of San Francisco in his garage. He kept them until now.”
Trevisan mentioned three times in her opening remarks that Marissa had left her home on the morning of her disappearance with a map.
“They also found these plates,” she said pointing to a displayed photograph of two yellow-on-blue California license plates bearing the number 538RBE and with tags that expired in 1979.
Personette initially told arresting officers that he had never been to San Francisco.
Jurors were not told today that the suitcase also contained women’s underwear, nor that two knotted ropes were found stored in separate cars which are said by investigators to be the same width as the ligature used to choke Marissa to death.
Trevisan said that DNA was recovered from multiple locations on the victim’s clothing – including on a piece of gum found stuck to the girl’s sweater.
“And when he was interviewed, he was told what this was about…he’s not surprised, he’s not outraged, he’s calm, he’s cold, he just repeated to himself: ‘huh, piece of gum’ – it’s quite telling.”
Prosecutor Heather Trevisan
“And when he was interviewed,” she said, “he was told what this was about…he’s not surprised, he’s not outraged, he’s calm, he’s cold, he just repeated to himself: ‘huh, piece of gum’ – it’s quite telling.”
Jurors were told they will hear testimony from a woman who says Personette beat and raped her in New Jersey in 1979 as a 16-year-old girl, a charge on which he was tried and acquitted.
The woman is adamant Personette was her attacker and intends to take the stand.
“But what happened to her she not deserve,” said Trevisan. “What happened to her was not her fault. And what happened to her is illustrative of what this man did to Marissa Harvey as well.”
Remarkably Personette was also tried and acquitted of a second attack in New Jersey at around the same time – in that case a woman says she fought off what bore the hallmarks of an attempted abduction.
A third woman, a jogger in San Francisco’s Golden Gate Park, says Personette tried to kidnap her at knifepoint around the time of Marissa’s death. Her boyfriend came to her aid, allowing her to escape. She came forward after recognizing the defendant’s mugshot released following his 2021 arrest.
Although listed as a potential witness, prosecutors earlier indicated she will not now testify.
Unless Personette testifies, in which case prosecutors may be allowed to put it to him, the jury will not learn of his convictions for indecent exposure and drunk and disorderly conduct in New Jersey.
Within seconds of beginning his opening remarks, defense attorney Adam Gasner tacitly conceded that his client’s DNA was found on Marissa Harvey’s clothing. But, he said, DNA from other people was found on her clothes and on a cigarette paper found at the scene where the body was found.
“The forensic record shows multiple DNA contributors at the scene and on Ms Marissa Harvey,” Gasner told the jury. “Only one – designated as ‘unknown male 2’ – was later compared to Mr Personette. ‘Unknown male 1’ and ‘unknown male 3’ remain unassigned.”
“Where more than one plausible perpetrator exists the law requires a verdict of not guilty,” he said.
“Who doesn’t want to solve a cold case? Who doesn’t want justice for a young girl? But not at the sake of finding someone guilty when there is a doubt that is reasonable and cannot be excluded. The just and correct verdict based on the evidence is not guilty.”
Defense attorney Adam Gasner
“Who doesn’t want to solve a cold case?” asked Gasner. “Who doesn’t want justice for a young girl? But not at the sake of finding someone guilty when there is a doubt that is reasonable and cannot be excluded. The just and correct verdict based on the evidence is not guilty.”
Who specifically Personette might attempt to implicate was the subject of extensive pretrial argument – with prosecutors deriding defense attempts to accuse others as little more than a Hail Mary effort to pin the crime on innocent men. Another DNA profile on Marissa’s clothes was an anomaly, they said.
“I called the police right away…two policemen came and I said ‘my sister’s not home yet, please find her’ and they asked me some questions. And I told them she was 15 and they laughed at me and said, ‘oh, she’s gone off with a boy,’ and I said, ‘no, she is an innocent girl.’”
Miriam Wadiaeff
Also on Monday, the prosecution fielded its first witness, Marissa’s sister, Miriam Wadiaeff, who remained composed while testifying some ten feet from the man accused of killing her.
She told the court that, when their mother died, the girls were separated and Marissa was adopted by a family in New York. By 1977 she had traced her sister and traveled to her home in Port Washington NY to meet that year. Marissa was excited to visit Miriam in San Francisco and flew to the west coast in March 1978 to stay at her sister’s home on Page Street, one block from Golden Gate Park.
“We went to the ocean,” Wadiaeff said of the visit, “We went to the park. She was an excellent horse rider and before she could walk she could ride her horse. And, strangely enough, she was staring up at Sutro Heights and I asked her ‘Marissa, why are you staring up there?’ and she said ‘I want to ride my horse up there.’”
She described the panic when she realized that Marissa had not come home after being dropped off at the public riding stables at Golden Gate Park on Monday while she went to college.
“I called the police right away,” she explained to jurors. “Two policemen came and I said ‘my sister’s not home yet, please find her’ and they asked me some questions. And I told them she was 15 and they laughed at me and said, ‘oh, she’s gone off with a boy,’ and I said, ‘no, she is an innocent girl.’”
Wadiaeff marshaled friends into a search party and looked in vain for her sister across the park.
“They said that they had found a body and I remember being in a small room they took me to and they brought out a body – it was behind glass – and they asked me if that was Marissa.
“And I looked at her and I didn’t recognize her – she was all swollen and bruised. Her lip was thick. And I said, ‘no, that’s not my sister.’”
Wadiaeff told the court that she recognized the rainbow-patterned embroidery on her sister’s jeans.
Courtroom observers believe the defense strategy may seek to capitalize on the statute of limitations for sexual assault having expired under the law as it stood in 1978. By muddying the waters over Marissa’s killing the defendant could engineer an acquittal for murder which would see him walk free.
Eighty-year-old Personette, thin and gray-haired, cut a solitary figure in court. Throughout opening statements, he stared intently at a laptop displaying white-on-black captions and listened to proceedings through headphones.
Only once did he turn around to survey the courtroom.
The trial, before Judge Michael Rhoads and a jury of five men and seven women, is expected to last up to nine weeks.
Heather Trevisan and Katherine Wells are prosecuting. Adam Gasner appears solo for Personette.
The case continues.
Investigative genetic genealogy
Judge Michael Rhoads granted prosecutors’ request to keep details of forensic genealogy inquiries out of the public eye. These typically involve a suspect’s DNA profile being uploaded to genealogy websites like FamilyTreeDNA or GEDmatch to map potential relatives and build a suspect’s family tree.
San Francisco prosecutors said they wanted to shield the company they used from scrutiny, warning that publicity could drive users away and blunt a valuable investigative tool. They also aimed to protect the identities of relatives who may have quietly helped the investigation.
In other instances prosecutors may prefer to obscure investigators’ use of those genealogy databases that forbid access by law enforcement or other uses contrary to their terms of service. If questionable activity was undertaken with the benefit of a judicial warrant, they may wish to hide its existence.
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