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Murder of Julie Jensen

SOLVED2008Pleasant Prairie, Wisconsin3 SOURCES5 COVERAGE LINKSUPDATED JUL 2026
Julie Jensen
Julie Jensen — Credit: Disability Day of Mourning memorial (disability-memorial.org) · Copyrighted — editorial use, owner-approved 2026-07-11

Julie Carol Jensen (née Griffin), age 40, died on December 3, 1998, in the Carol Beach neighborhood of Pleasant Prairie, Wisconsin. Prosecutors alleged she was poisoned with ethylene glycol (antifreeze) and then suffocated while barely breathing in the marital bed she shared with her husband, Mark Jensen. Julie and Mark had met in 1981 while both worked or studied in Oshkosh, Wisconsin, and had two sons, David and Douglas, aged 8 and 3 at the time of their mother's death. At the time of her death, Julie worked part-time for the Port Authority in Chicago, and Mark Jensen was a branch manager for a St. Louis-based financial firm in Racine, Wisconsin.

Before her death, Julie Jensen had investigated her husband's behavior, checked his business planner, and photographed a note found there. She wrote a letter addressed to two law enforcement officers, gave it to a neighbor, and instructed that it be handed to police if anything happened to her. In the letter she stated she would never take her own life because of her children, and that she was suspicious of her husband's behavior and feared for her "early demise." She also referenced a brief affair she had had seven years earlier and noted her husband had not forgiven her for it.

At trial, Special Prosecutor Robert Jambois argued that Mark Jensen poisoned and then suffocated his wife. The trial was moved from Kenosha County to Walworth County due to pre-trial publicity. Defense counsel Craig Albee argued that Julie Jensen was depressed, had seen a therapist multiple times, was aware of her husband's affair with a co-worker, and had killed herself while framing her husband. Prosecutors presented evidence that Mark Jensen had discussed poisoning his wife with co-workers and a jailhouse associate, and had searched the internet for poison-related information. The admissibility of Julie Jensen's letter was legally contested under Sixth Amendment confrontation-clause protections, but the Wisconsin Supreme Court permitted its use under the "forfeiture by wrongdoing" doctrine, relying on the U.S. Supreme Court's ruling in Crawford v. Washington.

On February 22, 2008, a jury convicted Mark Jensen, then 48, of first-degree intentional homicide after more than 30 hours of deliberation. Kenosha County Circuit Court Judge Bruce Schroeder sentenced him on February 27, 2008, to life imprisonment without parole. His sons publicly supported him and asked the judge to grant a parole date.

On December 19, 2013, a federal judge overturned the conviction, finding that use of the letter violated Jensen's constitutional right to confront witnesses, and ordered his release within 90 days. The Seventh Circuit Court of Appeals upheld this decision on September 8, 2015. Prosecutors moved to retry Jensen in January 2016. A Kenosha judge reinstated the original conviction in September 2017, but Wisconsin's Court of Appeals reversed that decision in February 2020 and remanded the case for a new trial, ruling the letter and a related voicemail would not be admissible. Jensen's second trial began January 9, 2023, before Judge Anthony Milisauskas; he was found guilty on February 1, 2023, and sentenced again to life without parole on April 14, 2023.

Start hereVIDEOHusband Caught Poisoning Wife with AntifreezeAnnie Elise · YOUTUBE · 1 min

Key facts

Victims
Julie Jensen
Date
2008
Location
Pleasant Prairie, Wisconsin
Case status
solved

Case timeline

  1. 1981

    Julie Griffin met Mark Jensen while both were connected to a local college and Sears in Oshkosh, Wisconsin.

  2. 1998-11-21

    Julie Jensen wrote and photographed a letter expressing suspicion of her husband, to be given to police if anything happened to her.

  3. 1998-12-03

    Julie Jensen was found dead in the couple's home in Pleasant Prairie, Wisconsin, allegedly poisoned with antifreeze and suffocated.

  4. 2008-02-22

    Mark Jensen was found guilty of first-degree intentional homicide after more than 30 hours of jury deliberation.

  5. 2008-02-27

    Judge Bruce Schroeder sentenced Mark Jensen to life in prison without parole.

  6. 2013-12-19

    A federal judge overturned Jensen's conviction and ordered his release within 90 days, citing Confrontation Clause violations.

  7. 2015-09-08

    The U.S. Court of Appeals for the Seventh Circuit upheld the district court's decision overturning the conviction.

  8. 2016-01

    Prosecutors decided to retry Mark Jensen for the murder of his wife.

  9. 2017-09-01

    Kenosha Circuit Judge Chad Kerkman reinstated Mark Jensen's conviction.

  10. 2020-02-26

    Wisconsin's Court of Appeals, District II, reversed the reinstatement and remanded the case for a new trial, ruling the letter and a voicemail inadmissible.

  11. 2023-01-09

    Mark Jensen's second trial began before Kenosha County Circuit Court Judge Anthony Milisauskas.

  12. 2023-02-01

    Mark Jensen was found guilty at the second trial.

  13. 2023-04-14

    Mark Jensen was sentenced again to life in prison without the possibility of parole.

Best coverage

Titles and descriptions are the creators’ own and may not reflect current legal status; see the dossier above for sourced case facts.

VIDEO

Annie Elise / 1 min

Husband Caught Poisoning Wife with Antifreeze

VIDEO

Crime Weekly / 1 hr 41 min

Julie Jensen: The Verdict (Part 3)

VIDEO

Crime Weekly / 1 hr 32 min

Julie Jensen: Psychological Warfare (Part 1)

VIDEO

Crime Weekly / 1 hr 36 min

Julie Jensen: The Letter (Part 2)

VIDEO

That Chapter / 26 min

The Case of Mark Jensen

People

  • Mark Jensen

    CONVICTED

    Convicted of first-degree intentional homicide in 2008 for the murder of his wife Julie Jensen; conviction overturned in 2015 on appeal; convicted again at a second trial in February 2023 and sentenced to life without parole.

  • Julie Jensen

    VICTIM

    Died December 3, 1998, in Pleasant Prairie, Wisconsin, allegedly poisoned with antifreeze and suffocated by her husband.

Roles reflect public records and court outcomes at the time of writing — supporting citations are on file under Sources.

Archival records

  • Julie Jensen

    portrait victim

    Julie Jensen

    Credit: Disability Day of Mourning memorial (disability-memorial.org) · Copyrighted — editorial use, owner-approved 2026-07-11 · Source

Places

Common questions

What happened to the victim?
Julie Jensen was found dead in her Pleasant Prairie, Wisconsin home on December 3, 1998, after being poisoned with antifreeze. A letter she wrote before her death naming her husband, Mark Jensen, as a suspect became central evidence. Mark Jensen was convicted in 2008, had that conviction overturned on appeal in 2015, and was convicted again at a second trial in 2023.
Where did the murder happen?
Pleasant Prairie, Wisconsin.
Who was convicted?
Mark Jensen (Convicted of first-degree intentional homicide in 2008 for the murder of his wife Julie Jensen; conviction overturned in 2015 on appeal; convicted again at a second trial in February 2023 and sentenced to life without parole.).
What is the current status of the case?
Status: solved. Last verified July 2026.

Sources

  1. ENCYCLOPEDICMurder of Julie JensenWikipedia · 2026-07-05
  2. OFFICIAL / AGENCYContemporaneous coverage — wicourts.govwicourts.gov · 2026-07-05
  3. COURT RECORDContemporaneous coverage — media.ca7.uscourts.govmedia.ca7.uscourts.gov · 2026-07-05

Record history

First published
JUL 05, 2026
Last verified against sources
JUL 05, 2026