Some true crime stories are hard to believe and Mary McGriff’s story is one of them.
When she was just 15 years old, she survived a brutal and gruesome attack that would have left other people dead.
Even though she lost both her hands, she has refused to let the tragedy define her.
Instead, she has become a powerful voice for change, fighting to make sure others don't suffer the way she did.
Let's get into the details
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| Mary before her attack |
The Early Years: Who Was Mary Vincent?
Mary Vincent, who later became known as Mary McGriff, was born in 1963 in Las Vegas, Nevada.
She was one of seven children in her family, according to Wikipedia.
Her father worked as a mechanic, and her mother was a blackjack dealer.
Mary loved creative art from a very young age, especially dancing and drawing.
At just 13 years old, she performed a solo dance routine at the prestigious Miss Universe Pageant, showcasing her potential as a performer.
However, things at home started to fall apart when her parents went through a painful divorce.
Mary felt lonely and ignored, and like many teens in that situation, she just wanted to get away from it all.
In the fall of 1978, when she was just 15, Mary ran away from home and started hitchhiking to Nothern California.
Back then, it was a common way for teenagers to travel, even though it was dangerous.
Mary spent a short time in Berkeley, sleeping on the streets, as reported by Keypennews.
But after feeling homesick, she decided to visit her grandfather who lived near Los Angeles.
Mary didn’t have any money for the trip, so she chose to hitchhike again.
She had no idea that this simple decision would change her life forever.
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| Mary after her attack |
The Day Of the Attack
On September 28, 1978, Mary began hitchhiking, hoping to reach her grandfather’s home in Los Angeles.
After several hours on the road, she became tired so she decided to look for a free ride.
Around 7:30 PM, while Mary stood on Interstate 5 near Modesto, California, with other hitchhikers, a blue 1968 Dodge van pulled over
The driver, later identified as Lawrence Singleton, told the hitchhikers he could only give a ride to the female passenger, Mary, even though the van’s cargo area was empty.
Two male hitchhikers nearby, who sensed something was wrong, warned Mary not to accept the ride.
But Mary, tired from hours of travel and eager to keep going, ignored their advice and climbed into the van's passenger seat.
Sadly, she didn’t know that this decision would lead to a night of unimaginable violence.
For the first hour into the journey, everything seemed normal.
Singleton stayed on the right road and had little conversations with Mary, which made her feel relaxed.
Around 9:00 PM, Mary dozed off thinking she was safe, but when she woke up, she found out they were no longer on the right road.
When Mary demanded an explanation, Singleton claimed to have taken a wrong turn.
She then asked him to turn back, but he pulled the van over saying he needed to ease himself.
According to Keypennews, Mary said that she knew this was her only chance to either escape or die trying.
After Singleton exited the driver's side, she quietly opened her door, came down and prepared to run.
As Mary bent down to tie her shoe, Singleton swiftly walked around the van and hit her in the head with a 3-pound sledgehammer.
Mary collapsed and became unconscious.
When she woke up, Singleton had already dragged her into the van’s cargo area and tied her wrists with nylon rope
He then repeatedly raped her through out the night, while she drifted in and out of consciousness from blood loss and head trauma.
In one final act of cruelty, he used a 14-inch butcher knife to cut off both of her hands just below the elbows.
According to detectives, Singleton cut off her hands to prevent her from being identified by fingerprints if her body was found.
Thinking Mary was dead or would die soon, Singleton pushed her over a 30-foot cliff into a culvert.
He then drove away, convinced he had gotten away with the perfect crime.
Against all odds, Mary regained consciousness in the culvert and managed to crawl out to the main road.
Despite losing nearly 50% of her blood, multiple broken ribs, and a traumatic brain injury, she made the choice to survive.
She used dirt from the culvert floor to cover her severed hands, thereby creating makeshift clots.
Once on the road, she began walking, desperately searching for help, with her face still covered in blood.
The first car Mary saw had some men in it, but they quickly sped off when they saw her naked and covered in blood.
Luckily, the second vehicle, driven by newlyweds John and Linda, immediately stopped.
The were actually headed to their honeymoon and had made a wrong turn.
So while they were looking for the right road to continue their journey, they stumbled upon Mary
The couple wrapped Mary in a blanket and rushed her to Doctors Medical Center in Modesto at about 9 AM , where trauma teams began emergency treatment.
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| Mary drawing with her prosthetic arms |
Lawrence Singleton’s Arrest and Initial Conviction
After Mary Vincent’s rescue on September 29, 1978, Modesto police immediately launched a criminal investigation.
Detectives interviewed Mary at Doctors Medical Center, where she provided a detailed physical description of her attacker, including his facial features, clothing, speech patterns, and the distinct smell of diesel fuel and tobacco in his van.
Her description was so accurate that a police sketch artist created a composite drawing that matched Lawrence Singleton with striking accuracy.
On October 5, 1978—just seven days after the attack—a neighbor in Singleton’s hometown of Citrus Heights recognized the sketch and alerted authorities.
Singleton was arrested the same day at his secondary residence in Reno, Nevada.
Police impounded his blue 1968 Dodge van, where forensic investigators discovered bloodstains matching Mary’s type, strands of her hair, and fibers from her clothing.
The sledgehammer and butcher knife used in the attack were also recovered from his toolbox.
Singleton was extradited to California and charged with kidnapping, rape, mayhem (intentional disfigurement), and attempted murder.
His trial began in March 1979 at the Stanislaus County Superior Court.
Mary, still recovering from her injuries, testified against him while wearing early versions of her prosthetic arms.
On April 13, 1979, Judge Robert B. Sanderson sentenced Singleton to 14 years and 4 months in prison.
Back then, crimes like this didn’t carry harsh punishments like they do now.
The maximum sentence Singleton could get under California’s 1978 laws was just 14 years.
People were outraged, especially because the charge of “mayhem” for cutting off Mary’s hands was treated like a simple assault at the time.
As deputies led Singleton from the courtroom, he leaned toward Mary and whispered:
“If it’s the last thing I do, I’ll finish the job.”
Singleton was sent to Folsom State Prison to begin his sentence, but he ended up serving only eight years before being released on parole for “good behavior.
When Mary heard he was out, she remembered the threats he made to her in the courtroom and went into hiding, terrified for her life.
But it wasn’t long before Lawrence committed another brutal crime—one that landed him on death row.
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| Lawrence Singleton at the time |
Lawrence Singleton’s Second Crime and Conviction
Following his parole in 1987, communities across California were outraged and refused to let Singleton settle anywhere near them.
As a result, authorities had no choice but to place him in a trailer on the grounds of San Quentin State Prison until his parole ended in 1988.
After that, Singleton moved to Tampa, Florida—his childhood hometown.
But even there, people protested and refused to let him live with them. .
According to LA Times, someone even offered him $5,000 to leave the state after a homemade bomb went off near Lawrence Singleton’s home.
Thankfully, no one was hurt during the bombing and Singleton kept a low profile thereafter—but that silence didn’t last long.
Ten years after his release, he struck again.
On February 2, 1997, Singleton came across 31-year-old Roxanne Hayes, a mother of three who worked as a sex worker, near his home.
Witnesses later said they saw the two arguing outside before eventually going into the house together.
The following morning, neighbors called police after hearing screams from Singleton’s property.
When Officers arrived, Singleton was covered in blood, trying to clean his floors with bleach.
Inside the house, they found Roxanne Hayes' body in a back room—she had been stabbed 17 times, likely with a hunting knife.
According to The Hillsborough County Medical Examiner, she was raped before her death.
Singleton was arrested at the crime scene and charged with first-degree murder.
During the interrogation, Singleton admitted to stabbing Roxanne Hayes but claimed it was self-defense, saying she tried to rob him.
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| Lawrence Singleton during his second arrest |
Prosecutors rejected Singleton’s self-defense claim, pointing to his violent past, lack of any stolen property, and strong forensic evidence.
During his 1998 trial, Mary Vincent, who was now an adult, courageously took the stand.
She recounted her brutal attack and also told the court of the chilling threat Singleton made to kill her if he ever got out.
On August 21, 1998, a jury convicted Singleton of premeditated murder after three hours of deliberation.
On December 11, 1998, Circuit Judge J. Rogers Padgett sentenced Singleton to death by lethal injection.
The defense argued his advanced age (72) warranted life imprisonment, but prosecutors emphasized his escalating brutality.
Singleton remained on death row at Florida State Prison for three years and all of his appeals were denied.
On January 28, 2001, he died of metastatic lung cancer at the prison medical unit before his execution could be carried out.
Before Singleton was cremated, the Hillsborough County Sheriff’s Office preserved his DNA, hoping it might help solve other unsolved cold cases in the future.
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| Mary McGriff |
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| Mary McGriff and her current husband |
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| Mary McGriff |
After surviving the attack and testifying in both of Lawrence Singleton’s trials, Mary Vincent (now Mary McGriff) focused on rebuilding her life.
She married and had two sons, though her first marriage ended in divorce, according to Wikipedia.
In the late 1980s, she moved to Washington state, where she still resides with her second husband, Tony McGriff.
Mary became an advocate for crime victims, speaking publicly about her experience to push for legal reforms.
She helped influence California’s "Singleton Bill," which increased penalties for violent crimes involving torture.
Despite her advocacy work, she largely avoids media attention, preferring a quiet life in Vaughn, Washington.
An accomplished artist, Mary works primarily with chalk pastels, creating vibrant portraits and abstract pieces, according to Blurredbylines.
Today, Mary lives privately, focusing on her art, family, and occasional advocacy work.
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