The Antifreeze Murders: 5 Shocking Facts About Diane Staudte, The Mother Who Poisoned Her Family

The case of Diane Staudte remains one of the most chilling examples of familial betrayal in modern true crime history. As of late 2025, the Missouri mother is currently serving a life sentence without parole for the shocking murder of her husband, Mark Staudte, and her son, Shaun Staudte, in a plot that also included the attempted murder of her daughter, Sarah Staudte. The details of the crime—slowly poisoning her family with antifreeze—continue to horrify and fascinate, especially with recent prison interviews shedding new light on her mindset. The Staudte family tragedy, which unfolded in Springfield, Missouri, between 2012 and 2013, exposed a sinister mother-daughter conspiracy driven by a desire for a "different life" and financial gain. The case serves as a stark reminder that evil can lurk behind the most seemingly normal façades, as Diane Staudte was a well-known church organist and nurse in her community.

Diane Staudte: A Complete Biography and Profile

The life of Diane Staudte, prior to her arrest, was marked by an outward appearance of suburban normalcy that sharply contrasted with the dark reality of her actions.

• Full Name: Diane Staudte (née Hupp)
• Date of Birth: 1963 (Approximate)
• Age at Arrest: Approximately 50 years old (Arrested June 2013)
• Hometown: Springfield, Missouri
• Occupation: Licensed Practical Nurse (LPN) and Church Organist
• Spouse: Mark Staudte (Married 28 years, deceased)
• Children: Rachel Staudte (Co-conspirator), Shaun Staudte (Victim, deceased), Sarah Staudte (Victim, survived), and one other daughter (unnamed in most reports).
• Victims: Mark Staudte (Husband), Shaun Staudte (Son), and attempted murder of Sarah Staudte (Daughter).
• Crime: First-degree murder and second-degree murder, attempted murder.
• Method: Poisoning with Ethylene Glycol (Antifreeze).
• Sentence: Life in prison without the possibility of parole (for the murder of her husband and son).
• Current Status: Serving her sentence in a Missouri correctional facility.

The Chilling Timeline of The Staudte Family Poisonings

The murders were not a sudden act of violence but a slow, calculated plot that unfolded over several months. The method of using antifreeze (Ethylene Glycol) allowed the symptoms to mimic natural illnesses, initially fooling doctors and police.

Mark Staudte’s Mysterious Death

Mark Staudte, Diane’s husband of 28 years, was the first victim. He began experiencing flu-like symptoms and severe seizures in the spring of 2012. Diane, a licensed nurse, initially dismissed his condition as a common illness.

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He died on April 8, 2012, at the age of 61. The cause of death was initially attributed to natural causes, possibly a stroke or illness, and his body was cremated, destroying key forensic evidence.

Investigators later learned that Diane had been slowly adding antifreeze to his soda over a period of time. Her motive was a desire to be free from her husband and an alleged bid for financial gain, including an insurance payout.

The Murder of Shaun Staudte

Just five months after her husband’s death, Diane targeted her 26-year-old son, Shaun Staudte, who had autism. Shaun was dependent on his family and was reportedly seen as a burden by his mother and sister, Rachel.

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Shaun began to suffer from the same mysterious, debilitating symptoms as his father. He was poisoned with antifreeze mixed into his Gatorade and other drinks.

Shaun Staudte died on September 2, 2012. His death was also initially ruled as natural, baffling the medical community but raising no immediate suspicion of foul play.

The Attempted Murder of Sarah Staudte

In June 2013, the mother-daughter duo attempted to complete their sinister plan by targeting the last remaining family member in the home, 24-year-old Sarah Staudte. Sarah was a college student who was reportedly struggling with debt, which Diane claimed was a stressor.

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Sarah was rushed to the hospital in critical condition, suffering from a brain bleed, multiple organ failure, and severe neurological damage. Doctors initially struggled to diagnose her condition.

It was a crucial moment in the case. Unlike her father and brother, Sarah survived the poisoning, but the severity of her symptoms finally triggered a long-overdue investigation.

The Pastor’s Tip and The Mother-Daughter Confession

The breakthrough in the Staudte case came from an unlikely source: a tip to the Springfield Police Department from Pastor Jeff Sippy of the Redeemer Lutheran Church, where Diane was the organist.

Pastor Sippy had grown suspicious after hearing Diane talk about her family's deaths and Sarah’s sudden illness. He told police he believed Diane was poisoning her family, prompting them to exhume Shaun and Mark’s bodies for forensic testing.

The exhumation confirmed the presence of lethal levels of ethylene glycol in both bodies. This evidence led to the arrest of Diane and her daughter, Rachel Staudte, in June 2013.

During her interrogation, Diane Staudte initially confessed to the crimes, admitting she put antifreeze in her family's drinks over several days. She chillingly told detectives, "I'm not a perpetual killer. I'm just stupid."

Where Are Diane and Rachel Staudte Now?

The two perpetrators of the "Antifreeze Murders" were convicted and are currently serving time in Missouri prisons, but their legal paths differed significantly.

Diane Staudte’s Life Sentence

Diane Staudte pleaded guilty to two counts of first-degree murder and one count of attempted murder in 2016 to avoid the death penalty. She was sentenced to life in prison without parole. Her case has been the subject of numerous true crime documentaries and recent television specials, including ABC's *20/20*, which featured an exclusive prison interview.

In a shocking twist after her confession and plea, Diane has since attempted to recant her confession, claiming she was coerced by the police. However, her conviction stands, and she will spend the rest of her life in prison.

Rachel Staudte’s Involvement and Plea Deal

Rachel Staudte, who was 22 at the time of the crimes, played a significant role as her mother's co-conspirator. She admitted to researching how to murder people with poison and helping her mother carry out the plot.

Rachel accepted an Alford plea for two counts of second-degree murder and one count of first-degree assault, meaning she maintained her innocence but admitted the prosecution had enough evidence to convict her. She was sentenced to two consecutive life sentences plus 20 years, with the possibility of parole, making her eligible for release after approximately 42 years.

The Current Condition of Sarah Staudte

Sarah Staudte is the sole surviving victim of her mother and sister’s murderous plot. Her story is one of incredible resilience and trauma.

Sarah survived the poisoning but was left with permanent, life-altering injuries. She suffered a brain bleed and severe organ damage that required extensive medical intervention and rehabilitation.

While she has mostly remained out of the public eye to recover and rebuild her life, Sarah Staudte's survival was the key factor that finally brought her mother and sister to justice. Her critical condition was the red flag that led to the investigation, the exhumation of her father and brother's bodies, and the subsequent arrests, ensuring the mother-daughter killing spree was brought to an end.