Ripples in a Pond: The White Rock Lake Machete Murder



A pebble thrown into a still pond does not sink without a trace. It causes a circular ripple with an expanding radius. As anyone who has faced a math quiz can tell you, the greater the mass of the rock, the more water displaced and the bigger the radius will grow. A murder is the same, a single act that spreads its zone of impact in an ever widening ripple. Unlike that still pond, those touched will never be the same again.

October 12, 2015 started like any other Monday for Dave Stevens. Dave had been a passionate runner since he was a child and had completed 11 marathons. He was training for the Dallas Marathon just a few weeks away. Sometimes he ran with Patti, but on this day he was alone.

Every Monday, Wednesday, and Friday Dave ran 10 miles on the White Rock Creek Trail, part of the Dallas Trail System that winds through neighborhoods and parks including Valley View, Anderson Bonner, Orbiter, and Harry Moss. The trail is a favorite of runners and bikers because it’s not overly crowded and fairly flat.

He set off that day at 7 am, just before the sun would rise. He parked at the Valley View trail entrance and set off. Everything was as it always was on his morning run, until Dave passed through Harry Moss Park, and into the dark place underneath the Walnut Hill overpass.

Thomas Linze Johnson was also in a dark place.

Just three years earlier, Johnson’s future had seemed bright. He was a star running back at Dallas Skyline High School. Intensely recruited, ESPN ranked Johnson as the number three receiver in the entire nation. He initially committed to Texas, but changed his commitment to Texas A&M. In 2012, he played ten games for the Aggies, catching 30 balls for 339 yards.


On November 10, 2012, 15th ranked A&M defeated Number 1 ranked Alabama. Johnson caught several passes from eventual Heisman trophy winner Johnny Manziel (aka Johnny Football). But after that game, instead of savoring the triumphant moment, he became very upset.

According to his college roommate, Johnson had become reclusive, spending hours alone reading his Bible and smoking marijuana. His father says Johnson admitted smoking K2, a potent synthetic marijuana. Others would say he had become obsessed with the movie The Book of Eli and compared himself to Denzel Washington’s character, a nomad in a post-apocalyptic world who hears a voice giving him an important task to complete.

The next day he missed practice. When he missed a second practice, coaches began looking for him and contacted his mother who had no idea where he was. For three days his whereabouts were a mystery until he was found walking down a road back in Dallas. He had simply walked away from college and football, carrying a knapsack of Bibles and an engagement ring he had bought for his girlfriend. He never went back.

Johnson spent three days in a court ordered psychiatric facility where there was finally a clinical diagnosis of schizophrenia. Upon release, he refused all treatment. Over the next two years of Johnson’s life, he struggled with both mental health and substance abuse. His family was at a loss for how to help him when he became delusional and resistant to treatment.

According to a September 22, 2016 ESPN article, his relationship with his mother proved problematic. She could be both a help and a hindrance to him getting the help he needed. His mother rejected the diagnosis saying to ESPN reporters “they threw around schizophrenia. I don’t know. I don’t know much about it…I think it was something else going on that was mind-altering. In some form or fashion, his mind had been altered.”

According to the National Institute of Mental Health (NIMH), schizophrenia generally starts anywhere between the ages of 16 to 30 years old, but the most common time for men is late adolescence to early adult hood. When people think of schizophrenia, they think of the most obvious and dramatic symptoms such hallucinations and delusions, but schizophrenia is so much more. It’s an entire cornucopia of symptoms including thought disorders and cognitive disorders.

People with schizophrenia often display what is called “flat affect” meaning a lack of facial expression and vocal tone. You can definitely see this in pictures of Thomas Johnson after the onset of his illness. He doesn’t even face the camera, just staring off at nothing. In fact, those suffering from schizophrenia often experience diminished enjoyment in things. They have difficulty beginning and finishing normal tasks. They develop trouble focusing and an inability to pay attention. Memory and decision making can be severely impacted. And yes, there are often the hallucinations and delusions, the symptoms everyone knows, the symptoms that can lead to a complete break from reality.

In 2014, Johnson broke into his aunt’s home, stole money and her minivan. He drove down to College Station with the intention of reclaiming is old life. He mumbled to himself and walked in circles until he was asked to leave. His aunt, who said he had been causing problems for some time, pressed charges, although she later agreed to drop them if he completed a diversion program. Johnson continued having troubles, violating the rules of the program, and was placed on probation. He wasn’t compliant with his probation and a motion to revoke was filed by prosecutors for numerous violations including smoking pot.

There were people who tried to help Johnson, people who loved him. He lived with a family from his church for a while, but walked away from them just before meeting with a psychiatrist. Everyone in the family seems to have a story to tell about Johnson and the voices in his head. Everyone wanted to help him be better, but either they were in denial or didn’t know how or their efforts were met with too much resistance.

Nothing seemed to halt his downward spiral and by October 10, 2015, Johnson was on the verge of being homeless and very angry. He had cursed at his mother and she told him that if he was going to treat her that way, he needed to get out, so he took a knife, and he left.

October 12th, at 7:32 a.m., a man called 911 from the White Rock Creek Trail. He reported seeing a “large crazed man” wearing a hoodie by the tennis courts. Something about Johnson made this witness nervous enough that he took out his pepper spray, just in case. He said during the call that Johnson was following a jogger who noticed and began running faster.

At 7:55, a bike rider, identified by NBC Dallas-Fort Worth only as “Brandon,” came upon a scene which is the stuff of nightmares. He saw a man who looked like he was hacking at the ground, almost like he was chopping wood, but as Brandon got closer he could tell that the man had a machete and what he was hitting was a person, face down on the ground. He saw the man strike six or seven blows.

“It was apparent to me by the time I got close that there was nothing that could be done for that person. I heard a little bit of a yell from behind. I assume it was the guy with the machete yelling to stop. I just kept going and I just kept going.”

Johnson, then covered in blood, left the machete in Dave Stevens head and calmly walked to the equestrian center. He saw a man named Jason Hagen there and asked to borrow his phone which he used to place a chilling 911 call. “There’s a man laying down with a sword in his head.”

He went back to wait for the police by Dave Steven’s body. He told the first officer who arrived, “I just committed capital murder.” The officer asked Johnson what he meant and he replied, “It’s like when you don’t wake up.”

The shocking news of a murder on the White Rock Creek Trail broke almost immediately, but Dave didn’t run carrying his wallet or a cell phone and there are so many places along the trail to park a car. No one knew which car was his. His face was almost obliterated and unrecognizable. Police had no idea who he was.

Patti Stevens knew something was wrong when her husband didn’t come home from his job as an engineer at GE, but she didn’t listen to the news. She started looking for Dave and even drove to the lake where his SUV was parked and checked the lots where he typically parked until she found the SUV. Then she started calling the police. It was almost a full day before the connection was made and her worst nightmare was realized.
Patti and Dave met at Michigan State and by all accounts it was one of those storybook romances. They were best friends. Soulmates.

In 1989 they moved to Dallas and bought their dream home. Friends and family describe Dave as someone who was competitive within himself, but gentle, thoughtful, polite. A guy with a dry sense of humor. In an interview with the Dallas Morning News, Patti described her husband as a “sweet” man who gave her “everything I wanted.” She told the reporter “I’ll just say, Dave was the love of my life. And I’m lost without him.”

Patti kept it together through the funeral. Six days after she drove family to the airport, her neighbors became concerned when they didn’t see her. Police finally broke into the house. They found Patti’s body on the floor of the garage, dead of carbon monoxide poisoning. She had left pictures of her and Dave on her kitchen table and a scrawled note. The voices in Thomas Johnson’s head had claimed another victim.

Sadly, there is no satisfaction, no tidy resolution in this case. Dave and Patti Stevens—two ordinary people with no connection to the darkness inside Thomas Johnson’s head—are dead thanks to a chance meeting. Thomas Johnson is also beyond reach. In April 2016, Johnson was found incompetent to stand trial. He has remained that way in spite of treatment and has been housed in a mental health care facility.

This brief burst of violence has left continuing ripples. Family and friends are left to struggle with the questions of what might have been, what they might have done. If only someone had realized the tragic outcome of Johnson’s downward spiral. If only someone had recognized Patti’s despair and hopelessness. The church family who welcomed Johnson into their home have tried to visit him repeatedly, only to be turned away. He has refused to see anyone, not even his court appointed lawyer. He won’t take the hands stretching towards him. He remains locked in his mind which is more of a prison than bars could ever be. Biology has already handed Thomas Johnson a life sentence.

And let’s not forget the others marked by this day, random strangers caught in the ripples. Brandon who will never be able forget the horror of seeing a man with a machete. That first 911 caller who was afraid enough to take out his pepper spray. Jason Hagen who was approached by a bloody man demanding use of his phone. Let’s not forget those first responders, forced to bear witness to the worst humanity has to offer.

Let’s not forget the secondary responders, the prosecutors, mental health professionals, jurors, people forced to face the crime scene photos and deal with wreckage left behind.
Unlike so many murders, this story isn’t about good and evil. There are no villains or heroes in this tale. Just a very broken man with a machete who in a matter of minutes sent out ripples into the world that are still spreading.

If you have a loved one, family or friend, experiencing a mental health crisis, please seek help. There are so many national and local resources available that take mere minutes to locate. If you are in the DFW area, you can reach MHMR by calling or texting 817-335-3022 or 1-800-866-2465 (Toll free) or 817-569-4488 (TTY-TDD number for Hearing Impaired. Help is available 24/7. You’re not alone.

** UPDATE ** This story has been updated. Click the link to read the latest news. 

2 thoughts on “Ripples in a Pond: The White Rock Lake Machete Murder

  1. Pingback: Case Updates

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