PLEASANT PRAIRIE, Wis. — Nearly 25 years after the tragic death of Julie Jensen, a Wisconsin mother of two, justice was finally served with the conviction of her husband, Mark Jensen, in a case marked by chilling clues and a haunting letter from Julie herself.
A Life Cut Short
Julie Jensen, a 40-year-old native of Wisconsin, was found dead in her Pleasant Prairie home on December 3, 1998. Married to Mark Jensen since 1984, the couple had built a seemingly stable life with their two sons, David and Douglas, in a neighborhood near Lake Michigan.
Mark worked as a stockbroker, while Julie had previously held a Series 7 license and worked in the brokerage industry before choosing to stay home to raise their children. In the weeks leading to her death, Julie had been prescribed Paxil to treat depression.
Suspicious Circumstances and a Cryptic Letter
Although Mark found Julie in bed, her death baffled authorities. An initial toxicology report was clean, but further tests revealed the presence of ethylene glycol — a toxic ingredient commonly found in antifreeze — in her bloodstream.
What made the case truly chilling was a letter Julie had written before her death, addressed to police and entrusted to a neighbor. In it, she named Mark as her “first suspect” should she die under suspicious circumstances, citing his odd behaviors and a cryptic shopping list that included “drug supply,” “razors,” and “syringe.”
Years of Harassment and Betrayal
Julie was no stranger to turmoil. Prior to her death, the family endured harassment involving disturbing phone calls and the placement of pornographic photos around their home — a campaign initially linked to Julie’s admitted affair with a co-worker.
Investigators later uncovered evidence that Mark was also having an ongoing affair with a colleague named Kelly LaBonte, who moved into the family home shortly after Julie’s death.
The Trials and Convictions
Mark Jensen was arrested for first-degree murder but initially posted a large bond and lived openly, remarrying LaBonte and starting a construction company. In 2006, a former co-worker testified that Mark had confessed hatred for Julie and admitted he “could kill her.”
Julie’s letter was finally admitted in court during the 2008 trial, alongside testimony from a jailhouse informant who alleged Mark had tried to finish killing Julie before their sons returned home. Mark was convicted and sentenced to life imprisonment.
However, the conviction was overturned on appeal due to the letter’s admission, and Mark was granted a new trial.
Justice Ultimately Served
At his 2023 retrial — this time without the letter — prosecutors presented new evidence. A computer expert testified Mark had been the one harassing Julie with pornographic images to punish her for her affair.
Once again, Mark Jensen was convicted of first-degree murder and sentenced to life without parole.
Julie Jensen’s foresight, courage, and that haunting letter helped reveal the truth behind her death, offering closure to a case that spanned decades and multiple trials.
