The Psychological Sadist

The Murder of Julie Jensen

Julie Griffin dropped out of nursing school because she couldn't bear to watch people suffer. Twenty years later, she would die at the hands of a man who found his life's purpose in making her suffer.

This is the story of how a shy, sensitive, midwestern girl who played accordion for her family became the victim of one of the most elaborate campaigns of coercive control and psychological torture I've ever seen, and how her former in-laws continue to desecrate her memory years after she is gone.

The Perfect Victim and The Perfect Predator

Julie Carol Griffin was born on February 26, 1958, in Kenosha, Wisconsin, a working-class city where auto plants employed half the town and everyone knew their neighbors. She was the only girl among six children; her brothers described her as "the perfect sister." Not perfect in an impossible way, but perfect in how she noticed when someone was sad, remembered birthdays without reminders, and tried to make peace when her brothers fought.

While her brothers competed in sports and roughhoused, Julie was the quiet observer, a straight-A student who had a knack for responding to others' needs before they even recognized those needs themselves. When Julie decided to major in nursing in college, no one was surprised; of course, she'd choose a profession that involved caring for others.

But she never graduated. In her final semester, during clinical rotations, Julie discovered that the pain of her patients affected her profoundly. She couldn't develop the professional distance that nursing requires. So she dropped out and found work as a bank teller, later earning her license as an investment broker—a practical career where she could be of service without witnessing physical suffering.

In 1981, working at Sears to save money, she met Mark Jensen.

Mark was born in Kenosha in 1959, a Boy Scout—a detail that would later seem bitterly ironic given the organization's emphasis on trustworthiness and honor. Where Julie was warm and emotionally attuned, Mark was described as introverted and emotionally stoic. In the late 1970s, these weren't necessarily red flags. Plenty of successful people are reserved. But in Mark's case, what seemed like introversion may have masked something darker: an inability or unwillingness to form genuine emotional connections.

They married in 1984 and settled in Pleasant Prairie, a suburb with a name that sounds like it came from a 1950s sitcom. Both worked in finance-related fields. They saved money and built careers. Julie dreamed of being a mom. Friends didn't report obvious red flags. Mark's emotional distance might have seemed like typical male reserve. Julie's tendency to accommodate, to prioritize others' needs over her own; these traits that made her such a beloved sister also made her vulnerable to someone who would exploit that generosity.

Julie had one quirk her family understood but Mark may not have: she didn't drink alcohol. This wasn't a moral stance but a practical one—alcoholism ran in her family, and Julie had decided early to avoid that particular genetic minefield. This level of self-awareness would later make claims of her being "unstable" ring particularly hollow.

The Trigger

In 1990, Julie gave birth to David, and Mark discovered he didn't want to share her with anyone, not even his own son.

Julie approached motherhood the way she approached everything: with total dedication. For Mark, David's arrival destroyed something that could never be repaired: his position as the sole focus of Julie's attention.

"He's not a hands-on father," friends would later say, using that polite Midwestern understatement that masks deeper truths. But it was worse than that. Mark didn't just fail to bond with his son—he actively resented the baby's existence. He complained that Julie was "too involved with the baby," as if a mother's love for her infant was somehow excessive, unreasonable, a betrayal.

Mark's solution was to make Julie's life impossible. He demanded she return to work full-time almost immediately. This wasn't about finances—they were both professionals with stable careers. This was about punishment. If Julie wanted to be a mother, she would have to earn it by being everything else, too.

Instead of helping with the baby or household, Mark became, as Julie later told friends, "more interested in drinking and partying and doing guy stuff." She found herself working full-time as an investment broker, caring for an infant alone, maintaining the house, and watching her husband choose bars and buddies over his family.

By 1991, Julie had reached her breaking point. She filed for divorce.

It was during this period—with divorce papers filed, feeling abandoned and desperate—that Julie made the mistake that would define the rest of her short life. She had a brief affair with a coworker. It lasted one weekend. Just two days of feeling wanted, appreciated, seen as something more than a servant and milk machine.

Then, in typical Julie fashion, she ended it immediately. The guilt ate at her. This wasn't who she was.

But Mark already knew. He’d been recording Julie's phone calls. The surveillance that would later become central to his torture campaign was already in place. When Mark discovered the affair through his recordings, he had two choices. He could have let the divorce proceed; after all, Julie had already filed. Or he could use this information differently.

He chose option two. After Mark discovered the affair through his recordings, he had leverage. Julie, wracked with guilt and desperate to keep her family together, withdrew the divorce filing. Whether through threats about custody, manipulation in counseling, or both, Mark ensured she would stay.

But Mark never forgave. As his friend David Nehring would later testify, eight years after learning about the affair, Mark's anger hadn't diminished at all. He'd filed the information away like a collector acquiring a rare coin. He finally had what he'd been waiting for: permanent permission to punish her.

Seven Years of Calculated Torture

The first pornographic image might have been in Julie's car, tucked under the windshield wiper like a parking ticket. A crude picture of male genitalia dominating a woman's face. Julie, modest and proper, would have been mortified. Who would do such a thing?

Then another appeared in the garden shed. Another in the mailbox. Soon they were everywhere—hidden in her purse, taped inside kitchen cabinets, slipped between folded laundry. Always the same theme: sexual degradation of women. Always appearing when Mark wasn't around to "protect" her.

The phone calls started too. Heavy breathing, hang-ups, sometimes whispered obscenities. Julie, already isolated with two young children, began to feel hunted in her own home.

And through it all, Mark played the protective husband. He hired a private investigator. He installed security cameras. He made a show of checking the doors and windows, of being vigilant—an impressive performance of husbandly protection that actually served to deepen Julie's dependence on him while allowing him to monitor her even more closely.

The cruelest part? Mark encouraged Julie to believe it was Perry Tarica, her former lover, behind the harassment. This served multiple purposes: it reminded Julie constantly of her "sin," made her grateful for Mark's "protection," and isolated her further—who could she tell about the harassment without admitting to the affair?

But Mark's control extended far beyond the fake stalking campaign. After their second son Douglas was born in 1995, Mark graciously "allowed" Julie to leave her job and stay home with the children. To others, this might have seemed loving. In reality, it was another form of control. Now Julie had no income of her own, no colleagues to notice if something was wrong, no escape route that didn't go through Mark.

The daily lists began in earnest. Each morning, Mark would leave detailed instructions:

• Clean the baseboards in the hallway

• Organize the garage shelves by size

• Weed the garden beds (even while seven months pregnant)

• Prepare dinner to be ready at exactly 6:15 PM

These weren't suggestions. They were orders, and failure to complete them would result in cold fury, verbal degradation, reminders that she was lucky he hadn't divorced her after her "betrayal."

But the most chilling form of control was the cordless phone Mark made Julie wear around her neck when he wasn't home. Like a collar on a dog, it served multiple purposes: he could reach her instantly, know she was always available to him, and remind her constantly that she was being watched. He monitored her gas mileage to track her movements.

Neighbors began noticing things. Margaret Wojt saw how Julie would sometimes stare into space with the thousand-yard stare that survivors of prolonged trauma develop. Ted Wojt witnessed Mark's verbal degradation of Julie—always with that cold, measured tone that was somehow worse than yelling. Ted later recalled Julie saying something that would prove prophetic: "Mark would kill me first, before he divorced me."

Then there was the incident with the dog. The family pet had committed an unforgivable sin: it showed affection to Julie's father during a visit. The dog was euthanized shortly after. The message to Julie was clear: love anyone too much, show affection to anyone but Mark, and there would be consequences.

Then came the moment that should have saved Julie's life. The private detective Mark hired eventually came to a stunning conclusion: he believed Mark was behind the harassment. Think about that—a professional investigator, hired by Mark himself, essentially told Julie, "Your husband is terrorizing you."

Julie's response reveals the depth of her psychological entrapment. She denied it, chose to believe Mark's denials. But here's the telling part: the harassment suddenly stopped. Not gradually, not after the "real stalker" was caught—it just stopped. Because Mark knew he'd been figured out.

This moment shows us Julie wasn't naive or stupid. She was given direct confirmation of what she probably suspected, but she couldn't psychologically afford to believe it. Accepting that Mark was her tormentor would mean accepting that her husband had tortured her for years, that the father of her children was a monster, that she was utterly alone. Sometimes denial is a survival mechanism.

Mark Jensen had found his calling. Some men golf. Some restore cars. Mark Jensen spent his leisure time psychologically destroying his wife.

The Endgame

By 1998, two things happened that would seal Julie's fate: Mark met Kelly LaBonte at his financial firm, and Julie applied for a job at Pleasant Prairie Elementary School.

The hypocrisy of Mark's affair would be stunning if we didn't already understand his psychology. For seven years, he'd tortured Julie for a weekend fling she'd had while he emotionally abandoned her. Now he was having a sustained emotional and physical affair, complete with love letters and future planning. In one email, he referenced having sex with Julie while thinking of Kelly.

Meanwhile, Julie's job application represented something Mark couldn't tolerate: independence. A part-time position perfect for a mother of two young boys. More importantly, it meant income of her own, colleagues who might become friends, hours when Mark couldn't monitor her.

Julie seemed to sense the danger. She began telling people she was afraid. She told Ted Wojt that she thought Mark was trying to poison her, that she’d find strange-tasting glasses of juice waiting for her. She told her son's teacher, Theresa DeFazio, "I think my husband's going to kill me." The woman who'd spent seven years in denial was finally, desperately, trying to create a record.

Most chilling was what she found in Mark's planner: a list in his handwriting that included "own drug supply," "bag hands," and "syringe." She photographed it, knowing it meant something terrible.

On November 21, 1998, Julie wrote:

"I took this picture [and] am writing this on Saturday 11-21-98 at 7AM. This 'list' was in my husband's business daily planner—not meant for me to see, I don't know what it means, but if anything happens to me, he would be my first suspect. Our relationship has deteriorated to the polite superficial. I know he's never forgiven me for the brief affair I had with that creep seven years ago...I'm suspicious of Mark's suspicious behaviors and fear for my early demise."

She gave this letter to the Wojts with instructions: if anything happens to me, give this to police.

In Mark's computer history, investigators would later find searches for ethylene glycol (antifreeze), poisoning symptoms, and how to make murder look like suicide. On the morning of December 3—the day Julie died—someone searched "ethylene glycol poisoning death" on the family computer.

On December 1, 1998, Julie saw Dr. Richard Borman. Mark had pressured her to go, likely hoping to establish a record of mental instability. But Julie didn't follow the script. When asked about her weight loss, she didn't claim depression but mentioned the state of her marriage. When asked if she was suicidal, she said firmly: "No. My boys mean everything to me."

The next day, Julie became violently ill after taking prescribed medication. ]Prosecutors would argue Mark had already begun poisoning her with antifreeze—a substance that tastes sweet, causes flu-like symptoms, and is nearly impossible to detect without specific testing.

On the morning of December 3, Pleasant Prairie Elementary called with wonderful news—Julie had gotten the job. Mark answered. His response: "Julie is sleeping and will be sleeping for a long time." Then he laughed.

The Enabling Continues

On December 3, 1998, Mark called 911 to report finding his wife dead. Detective Paul Ratzburg arrived at a scene that felt wrong. Mark's affect was off; he was too calm, too prepared with explanations. At Julie's funeral, witnesses reported Mark "laughing and carrying on" as if at a "cocktail party."

Within days, Mark threw out all of Julie's belongings. Kelly LaBonte moved in almost immediately. By Christmas, less than three weeks after Julie's death, Mark was hosting his company party, playing the gracious host.

When police questioned him four months later, Mark lied repeatedly. He denied any romantic relationship with Kelly despite emails proving otherwise. He claimed ignorance about who might have harassed Julie for seven years. He had explanations for everything, none of them believable.

Then Ted Wojt gave police Julie's letter.

It took four years to build the case, but in March 2002, Mark Jensen was charged with first-degree intentional homicide. After a 2008 conviction, a 2013 overturn on appeal, and a decade of legal battles, Mark was finally convicted again in 2023. Julie had been dead for twenty-five years.

Throughout the legal proceedings, Mark's defense argued that Julie committed "vengeful suicide" to frame him—a theory his parents, Dan and Florence Jensen, publicly embraced in a 2009 CBS "48 Hours" interview.

According to this theory, Julie, the woman who couldn't finish nursing school because she couldn't bear others' suffering, was actually a master manipulator who deliberately poisoned herself with antifreeze to frame Mark for murder, accidentally dying in her scheme.

In the CBS interview, Florence claimed Julie "wanted the kids, the house, and everything. She wanted it all. And she didn't want a husband." Dan added that Julie's letter was "all part and parcel of several years of her framing and planning how she was going to do this."

They claimed she was "a trained nurse" who would know exactly how much antifreeze to take. The reality? Julie dropped out of nursing school because she was too empathetic. She never practiced nursing a day in her life.

This defense theory requires believing that a devoted mother would risk orphaning her children for material gain. That she could fake terror for months. That multiple witnesses were fooled by her act. That she would write a false letter and accidentally kill herself in an elaborate frame-up.

The fact that Mark's parents could accept and promote such a theory, even if originated by the defense, suggests something about the family dynamics that shaped him. Mark likely grew up in a household where reality could be rewritten to suit the family narrative, where accountability was for other people, where women were viewed with suspicion and contempt, and where family loyalty meant never admitting wrongdoing.

Mark Jensen sits in prison for life. But at least in 2009, in his parents' version of reality, he was the victim, and Julie—dead for over a decade at that point—was still the villain.

Understanding the Sadist

Why would someone spend seven years psychologically torturing their spouse? Mark Jensen's case offers a window into a specific type of sadistic personality—one that derives self-worth from the domination and degradation of others.

Unlike crimes of passion or even planned murders for practical gain, Mark's behavior suggests something darker: he found meaning and pleasure in Julie's suffering. The pornographic images, the daily lists, the surveillance—these weren't means to an end. They were the point.

This type of sadism often stems from profound narcissistic injury. When Julie had her affair, she didn't just betray Mark—she shattered his self-image as the one in control. For someone with Mark's psychology, this wasn't a wound that could heal. It was an intolerable humiliation that demanded not just revenge, but ongoing proof of his power to punish.

The seven-year timeline is telling. Most people who kill their spouses in rage do so within weeks or months of discovering infidelity. Mark's sustained campaign suggests he discovered something more satisfying than murder: the daily restoration of his superiority through Julie's degradation. Each planted photo, each impossible task, each moment of fear was a small victory that temporarily soothed his narcissistic wound.

His parents' defense of him offers clues to his development. In families where image matters more than truth, where loyalty means never admitting fault, children learn that shame is intolerable and must be projected onto others. They never develop the capacity to process normal human emotions like hurt or disappointment. Instead, these feelings transform into rage and the need to punish.

Mark Jensen shows us what happens when someone who cannot tolerate shame marries someone whose empathy makes them willing to absorb it. He found in Julie the perfect victim—someone who would accept his projections, blame herself, try harder. Her very goodness enabled his evil, not because she was weak, but because she couldn't conceive of the depth of his pathology until it was too late.

Conclusion

Julie Jensen dropped out of nursing school because she couldn't bear to watch people suffer. This defining characteristic—her excessive empathy—made her vulnerable to a man who would find meaning in her pain.

Mark Jensen shows us how grudges become identity. He didn't just hold a grudge about Julie's affair, he built his entire identity around it. For seven years, being "the wronged husband" gave him purpose. The torture wasn't a means to an end; it was the end itself.

This case teaches us that the most dangerous abusers might be the ones who seem the most normal. They're not the ones who lose control; they're the ones who never lose control. They're the ones whose families will defend them against all evidence, even embracing theories that falsely cast their victims as the perpetrators.

Julie Jensen wrote a letter in 1998 because she finally understood what we now know: the most dangerous time isn't when the abuse starts, it's when you begin to see it clearly. If you recognize Mark's patterns in your own life, that recognition itself is an act of courage. Trust what you see.

National Domestic Violence Hotline: 1-800-799-7233

References

Court Cases

Jensen v. Schwochert, No. 10-CV-734, 2013 U.S. Dist. LEXIS 172652 (E.D. Wis. Dec. 19, 2013).

State v. Jensen, No. 2002CF000314 (Kenosha County Circuit Court 2008).

State v. Jensen, No. 2002CF000314 (Kenosha County Circuit Court 2023).

United States v. Jensen, 798 F.3d 574 (7th Cir. 2015).

Television Programs

CBS News. (2009, August 23). The letter [Television series episode]. In 48 Hours. CBS.

ABC News. (2023, February 10). Death foretold [Television series episode]. In 20/20. ABC.

NBC News. (2023). Secrets in Pleasant Prairie [Television series episode]. In Dateline NBC. NBC.

News Articles

A&E True Crime. (2023, October 19). Death by antifreeze: The murder of Julie Jensen. https://www.aetv.com/real-crime/murder-julie-jensen

Kenosha News. (2023, January 31). Mark Jensen retrial day 15: Jensen son takes stand, closing statements tomorrow. https://kenoshacountyeye.com/2023/01/30/mark-jensen-retrial-day-15-jensen-son-takes-stand-closing-statements-tomorrow/

Kenosha News. (2023, February 1). Mark Jensen found guilty in poisoning death of wife Julie Jensen. https://www.kenoshanews.com/news/local/crime-and-courts/mark-jensen-found-guilty-in-poisoning-death-of-wife-julie-jensen/article_db611562-a264-11ed-ab17-573c40a06d00.html

Kenosha News. (2023, April 15). Mark Jensen, Pleasant Prairie man convicted twice of killing wife, sentenced to life in prison without parole. https://kenoshanews.com/news/local/crime-and-courts/updated-mark-jensen-pleasant-prairie-man-convicted-twice-of-killing-wife-sentenced-to-life-in/article_42923b34-dad3-11ed-8053-77f6d8fef518.html

NBC News. (2023, October 13). Nearly 25 years after his wife was found dead in her bed, a Wisconsin man was convicted of poisoning her — again. https://www.nbcnews.com/news/us-news/mark-jensen-julie-poisoning-death-conviction-rcna118167

Primary Sources

Jensen, J. (1998, November 21). Letter to Pleasant Prairie Police Department [Evidence document].

Note: Additional witness testimony and trial transcripts from the 2008 and 2023 proceedings are part of the court record but are not separately published documents.