The Horrific Case Of Lawrence Singleton, The ‘Mad Chopper’ Who Hacked One Victim’s Arms Off

Published June 15, 2023
Updated June 20, 2023

In September 1978, Lawrence Singleton picked up a 15-year-old hitchhiker, Mary Vincent, then raped and mutilated her, before leaving her to die — and though he was sent to prison, this would not be his last crime.

Warning: This article contains graphic descriptions and/or images of violent, disturbing, or otherwise potentially distressing events.

Lawrence Singleton

Stanislaus County Sheriff’s OfficeLawrence Singleton, who chopped off a teenage hitchhiker’s arms, was later sent to death row in Florida.

On September 29, 1978, 50-year-old Lawrence Singleton offered a ride to a 15-year-old hitchhiker, Mary Vincent. But instead of driving her to her destination, he sexually assaulted her, cut off her arms, and left her to die on the side of the road.

After serving just eight years of his sentence for this merciless attack, Singleton was released on parole, leaving him free to attack again — and his next victim wasn’t fortunate enough to get away with her life.

This is the story of Lawrence Singleton, the “Mad Chopper” whose case sparked so much outrage in California that it led to new legislation that allowed for longer sentences for violent criminals:

Who Was Lawrence Singleton?

Born in Tampa, Florida on July 28, 1927, Lawrence Bernard Singleton was a merchant mariner by trade. Not much else is known about his early life. People reports that he was a heavy drinker and a mean drunk, and that he’d had two failed marriages and a fraught relationship with his teenage daughter by the time he met Mary Vincent.

“He had a deeply ingrained hatred and dislike of women,” Assistant Attorney General Scott Browne of Florida would later say.

This alleged hatred appeared to come to a boiling point when, at the age of 50, Singleton attacked his first known victim.

The Kidnapping Of Mary Vincent

In September 1978, Mary Vincent, a vulnerable 15-year-old runaway, was traveling to California to visit her grandfather, when, desperate for a ride, she reluctantly accepted one from a middle-aged stranger: Lawrence Singleton.

As they drove on, Vincent drifted off into a deep sleep. But when she woke up, she realized that Singleton was not following the agreed-upon route.

Angry, Vincent demanded that he turn the car around. Singleton dismissed her concerns, explaining that it was an innocent mistake. It wasn’t long before he was pulling over, telling Vincent that he needed to go to the bathroom. 

As the teenager stepped out of the car to stretch her legs, she was suddenly and ferociously attacked. Without warning, Singleton had lunged at her from behind, wielding a sledgehammer and hitting her sharply on the back of her head.

Once he had subdued her, Singleton forced the terrified girl into the back of the van, and she watched in horror as he tied her up. Then, Singleton sexually assaulted her.

Afterwards, he drove them to a nearby canyon, where he forced her to drink alcohol from a cup before raping her a second time. Repeatedly, Vincent begged him to let her go.

Lawrence Singleton Sketch

Stanislaus County PoliceMary Vincent provided law enforcement with a detailed description of her attacker.

When Singleton dragged her out of the car to the side of the road, Vincent thought he was finally setting her free. Instead, Vincent was subjected to one final act of unspeakable brutality.

“You want to be free? I’ll set you free,” Singleton said. Then, with a hatchet in hand, he chopped off both of her forearms. He pushed her down a steep embankment and left her to die there, in a culvert off of Interstate 5 in Del Puerto Canyon.

He thought he had gotten away with murder.

How Mary Vincent Helped Catch the ‘Mad Chopper’

Although she was bleeding profusely, and despite of the horrific ordeal she’d just faced, Mary Vincent stayed strong. Naked and holding her arms upright to stem the bleeding, she somehow managed to stumble three miles to the nearest road, where she flagged down a couple who, as luck would have it, had taken a wrong turn onto the road. They rushed the young girl to the hospital, where she was treated for her injuries.

While there, Vincent provided authorities with a detailed description of Singleton’s features. Police were able to create an incredibly accurate composite sketch of her attacker, offering a crucial lead in the hunt for the “Mad Chopper.”

In another stroke of luck, one of Singleton’s neighbors recognized him in the sketch and reported him to the authorities. Thanks to this tip, Singleton was quickly arrested and charged with the rape, kidnapping, and attempted murder of Mary Vincent.

Mary Vincent And Lawrence Singleton

Bettmann/Getty ImagesMary Vincent and Lawrence Singleton in a San Diego courtroom. Singleton received 14 years in prison for the attack.

Lawrence Singleton was found guilty and sentenced to fourteen years in prison — the maximum allowed in California a the time.

Lawrence Singleton Walks Free

Shockingly, after serving just eight years of his sentence, Singleton was released on parole in 1987 based on his good behavior.

The Tampa Bay Times reports that Singleton’s release caused outrage throughout the state of California. Many felt that he had not served enough time for his horrific crimes. The public outcry was so intense that even local businesses got involved, with one car dealer offering Singleton $5,000 to leave the state and never return.

But the anger and frustration felt by so many boiled over into something more dangerous when a homemade bomb was detonated near Singleton’s residence. Though no one was hurt, authorities were forced to place him in a mobile home at San Quentin State Prison until his parole expired the following year.

After his release, Singleton relocated to Tampa, the city where he had grown up, and began going by the name “Bill.” Tragically, it was in this city that Singleton committed his next heinous act: the murder of Roxanne Hayes, a working mother of three.

Roxanne Hayes

FindagraveRoxanne Hayes was murdered by Lawrence Singleton at his home in 1997.

The Mad Chopper Strikes Again

On Feb. 19th, 1997, a local house painter decided to swing by a client’s house in Tampa to do some touchup work — and instead witnessed a horrifying scene unfolding there.

Peering through a window, the painter saw the man he knew as “Bill,” completely naked and covered in blood, standing above a motionless woman on a sofa and stabbing her with a frenzied and vicious intensity. Later, the painter would say he heard the sound of bones crunching with each thrust — “like chicken bones breaking.”

Though the painter didn’t know it, it was Lawrence Singleton.

The woman was Roxanne Hayes, a 31-year-old mother of three who had turned to sex work as a means of supporting her family. On that fateful day, she had agreed to meet Singleton at his home for a payment of $20.

Later, Singleton would claim their meeting had quickly turned violent. He alleged that Hayes attempted to steal more money from his wallet, and as they wrestled for it, she picked up a knife and got cut in the struggle.

But the painter who witnessed the scene had a different account of the events. He claimed that by the time he saw Singleton attacking Hayes, she appeared already unable to defend herself. He never once saw her fight back.

The painter rushed to call the police, and when they arrived on the scene, it was clear that Hayes was beyond saving. Singleton was promptly arrested and charged with murder.

Mary Vincent’s Brave Testimony Against Her Attacker

In a remarkable display of courage, Vincent traveled to Florida to testify against Lawrence Singleton once more, this time on behalf of Roxanne Hayes. She played a pivotal role in Singleton’s ultimate conviction.

During the murder trial, Vincent bravely confronted her attacker, looking him in the eye as she identified him and delivering a powerful statement against his cruel acts.

“I was raped and I had my arms cut off,” Vincent told the jury. “He used a hatchet. He left me to die.”

The “Mad Chopper” was found guilty and sentenced to death row in Florida in 1998. However, no execution date was ever scheduled. On Dec. 28, 2001, at the age of 74, Lawrence Singleton died behind bars at the North Florida Reception Center in Starke due to cancer.

But Lawrence Singleton’s legacy lives on in one significant way. In large part due to the outrage caused by Singleton’s crimes and short initial sentence, California passed a series of laws that allowed for longer prison sentences for those convicted of violent crimes — including one law that made kidnapping with the intent of committing a sex crime punishable by life in prison.

After reading about the gruesome case of Lawrence Singleton, read about the murder of horror actress Dominique Dunne by her abusive ex-husband. Then, explore the case of Betty Gore, a woman who was butchered by her best friend.

Rivy Lyon
True crime expert Rivy Lyon holds a Bachelor's degree in criminology, psychology, and sociology. A former private investigator, she has also worked with CrimeStoppers, the Innocence Project, and disaster response agencies across the U.S. She transitioned into investigative journalism in 2020, focusing primarily on unsolved homicides and missing persons.
Maggie Donahue
Maggie Donahue is an assistant editor at All That's Interesting. She has a Master's degree in journalism from Columbia University and a Bachelor's degree in creative writing and film studies from Johns Hopkins University. Before landing at ATI, she covered arts and culture at The A.V. Club and Colorado Public Radio and also wrote for Longreads. She is interested in stories about scientific discoveries, pop culture, the weird corners of history, unexplained phenomena, nature, and the outdoors.