Diane Staudte case on Mother, May I Murder? season 2 - A detailed case overview

Investigation Discovery's Mother, May I Murder? season 2, episode 1, explores the case of a family in Springfield, Missouri, whose trust was shattered in the most unimaginable way. Diane Staudte, a nurse and mother of four, along with her daughter Rachel, turned everyday household items into tools of death.

Between 2012 and 2013, they poisoned family members with antifreeze, killing Diane's husband, Mark, and their son, Shaun, while attempting to murder their daughter, Sarah. What began as hidden resentments over financial burdens and daily frustrations escalated into a calculated plot that left investigators stunned.

The case exposed how ordinary family dynamics can hide dark secrets, with sweet-tasting antifreeze slipping undetected into drinks like Gatorade and soda. Season 2, episode 1 of Mother, May I Murder? aired on October 21, 2025, and is available for streaming on Max, Hulu, and Prime Video. It features survivor Sarah's recovery and detective insights.

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Mother, May I Murder? season 2, episode 1: The Staudte family dynamics and hidden pressures

Mother, May I Murder? season 2, episode 1(Image via Unsplash/ @JOSHUA COLEMAN)

The Staudte family resided in a small house in Springfield, Missouri, and appeared to be an ordinary family on the outside. Diane Staudte, a nurse, handled the family's finances. Her husband, Mark Staudte, who died at the age of 61, was a local band performer.

They were wed in 1985 and had four children: eldest daughter Sarah (born in 1988), son Shaun (born circa 1990, with autism and a seizure disorder), middle daughter Rachel (born in 1992), and youngest daughter Brittney (born circa 1997, with learning disabilities). The family had common interests in church activities and music, but underlying tensions mounted over the years.

Mark's occasional anger issues, including throwing objects during arguments, added tension, as did Diane's growing frustration with caregiving duties for Shaun and financial worries stemming from Sarah's student loans, according to People. Diane viewed her dependents as burdens, confiding later that Mark's substance issues with drugs and alcohol fueled her resentment.

"I hated his guts, I guess I'd just had enough," she said to the investigators as per ABC News.

Shaun, reliant on daily care, was seen as "more than a bother," interfering with Diane's routines. Sarah's independence clashed with Diane's expectations, as she lived at home post-college without steady work.

Rachel, quiet and close to her mother, shared these views, bonding over books and shared grievances. Brittney remained uninvolved, later describing the home as routine-filled yet oddly favoritist toward Rachel, according to ABC News.

Friends and relatives noticed oddities early. After Mark's death, bandmate Rob Mancuso recalled Diane behaved like "like she was hosting a party" at a gathering after her husband's memorial service, as reported by People. He added that she had "no sadness," initially attributing it to her coping mechanism.

Mark's brother, Michael, learned of Shaun's passing through family gossip, as there was no memorial service. According to ABC News, church pastor Jeff Sippy grew uneasy upon observing Diane's lack of emotion and later tipped off the police.

These pressures simmered without an outburst until Diane, using her nursing knowledge, researched undetectable poisons online, setting the stage for tragedy, as per People. The chilling transformation from caregiver to killer is revealed in Mother, May I Murder?

Also read: 7 true crime shows like The Many Deaths of Nora Dalmass

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Mother, May I Murder?: The series of poisonings and emerging suspicions

Mother, May I Murder? subject, Diane used antifreeze to kill her family members (Image via Unsplash/ @ Robert Laursoo)

The killings unfolded over 14 months, using ethylene glycol from antifreeze, which mimics flu symptoms and evades standard tests. On April 8, 2012, Easter Sunday, Mark collapsed at home after days of illness. Diane called 911, reporting cardiac arrest; no autopsy was done, and his death was ruled natural, linked to lifestyle factors.

She received $25,000 in insurance, which she used to purchase luxuries, such as a new car. Five months later, in September 2012, 22-year-old Shaun showed similar signs: slurred speech, yellow skin, and blood around his mouth from seizures. He died at home; the autopsy attributed it to his condition, missing the poison. Diane and Rachel had dosed him repeatedly, frustrated by his needs, as per People.

Tensions peaked with Sarah. On June 7, 2013, the 24-year-old drank tainted hot chocolate, suffering organ failure and a brain bleed. Hospitalized in a coma at Cox North, tests finally detected antifreeze, alerting staff on June 9. This prompted exhumations: Mark and Shaun's bodies tested positive for lethal levels, reclassifying deaths as homicides.

Police noted Diane's calm vacation plans amid the crisis, as well as an anonymous tip from Pastor Sippy.

"There was nothing in me that believed that [Mark's death] was of a natural cause," the pastor said, as per ABC news.

A home search uncovered antifreeze in Rachel's room, purchase records, and her journal foretelling deaths, which read:

"It's sad when I realize how my father will pass on in the next two months... Shaun... will move on shortly after."

Rachel admitted to helping mix doses, calling Sarah "equally unneeded," according to People. Diane sourced non-bitter antifreeze online, adding it to drinks over several days, a teaspoon at a time, for subtlety.

Brittney escaped notice, her note in Rachel's purse hinting at plans: "Only the quiet ones will be left." Sarah's survival cracked the facade, turning family grief into a homicide probe led by Detective Neal McAmis, a case that now stands among the most haunting stories retold in Mother, May I Murder?

Also read: 5 chilling details about Danielle Jennings's murder

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Arrests, legal outcomes, and family aftermath in Mother, May I Murder?

Mother, May I Murder? subject, Diane received three consecutive life sentences (Image via Unsplash/ @ Matthew Ansley)

Arrests came swiftly on June 20-21, 2013. Diane, 51, faced two first-degree murder counts for Mark and Shaun, plus assault on Sarah; Rachel, 21, was charged with second-degree murder as an accomplice. In interrogations, Diane confessed, bluntly admitting to adding doses of antifreeze to Gatorade and soda, according to People.

"I knew they were drinking antifreeze... I didn't know what else to do," she said.

Rachel also confessed after the discovery of the journal evidence, detailing her role. Both were held without bond in Greene County Jail. Trials spanned years. Rachel pleaded guilty in May 2015 to second-degree murder and assault, testifying against Diane for leniency. She was sentenced in March 2016 to two life terms plus 20 years, as per the Associated Press.

Diane's September 2015 trial featured Rachel's accounts. She entered an Alford plea in January 2016 to murder and assault, receiving three consecutive life sentences without parole, citing health issues over the death penalty. Sarah recovered with lasting damage, mobility loss, and neurological issues, now in assisted living, as per People.

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Mother, May I Murder? season 2, episode 1 is available on Max, Hulu, and Prime Video.

Edited by Riya Peter