Rob Mancuso wasn’t sure what to think of Diane Staudte’s demeanor after her husband died.
Mark Staudte, 61, of Springfield, Mo., died on Easter Sunday, 2012, after suffering from flu-like symptoms for several days.
Diane acted “like she was hosting a party,” Mancuso previously told PEOPLE about his longtime friend and bandmate, during a gathering following his memorial service. “There was no sadness.” I thought it was simply her way of grieving.”
Five months later, the couple’s 26-year-old son, Shaun, died, seemingly adding to the family’s bad luck.
He had flu-like symptoms before dying, as did Mark. However, the medical examiner determined that Shaun died as a result of prior medical causes, specifically seizures.
Diane appeared indifferent to her son’s death. “We found out he died from another relative,” Mark’s brother Michael Staudte told PEOPLE, adding that Diane did not hold a memorial service for Shaun.
Even more tragedy struck the family the following June, when Diane’s daughter Sarah, then 24, was admitted to the hospital with flu-like symptoms that were later diagnosed as organ failure.
While Sarah was fighting for her life, an anonymous tipper contacted police, claiming Diane had murdered her husband and son.
The caller, later identified as Diane’s church pastor, told Springfield police detective Neal McAmis that he, too, had noticed Diane’s lack of emotion following the deaths of her immediate family members.
“He talked about Diane’s lack of emotion when Mark died,” McAmis told PEOPLE. “He thought Diane’s reaction after Mark died was odd.”
The pastor stated that his suspicions were aroused when Shaun, who appeared healthy, died, and Diane appeared unconcerned about it.
Diane initially denied any involvement in Mark or Shaun’s deaths while being questioned by police. However, as her story began to unravel, according to interrogation transcripts, she blurted out, “To put it really short and sweet, I knew they were drinking antifreeze.”
When McAmis inquired whether she had given it to them, she replied, “I didn’t know what else to do.” She claimed she poisoned Mark for three days by putting antifreeze in his Gatorade and refused to take him to the hospital “because by then I hated his guts.”
Diane called Shaun “more than a bother,” and told McAmis she was upset with him because he didn’t work.
She said she was upset with Sarah because she had college loans due but no job.
Diane claimed she added “a couple of teaspoons” of antifreeze to their drinks because “they would do whatever they wanted and never helped.”
Diane was arrested on June 21, 2013, and charged with the murders of her husband and son, as well as the attempted murder of Sarah.
A Macabre Twist to the Story
While Diane was being questioned, detectives obtained a search warrant for her home, which yielded antifreeze, soda, and a journal belonging to Diane’s favorite child, Rachel.
What they read inside was terrifying. “It’s sad when I realize how my father will pass on in the next two months … Shaun, my brother, will move on shortly after,” he said.
Rachel initially claimed she was just describing her dreams. However, she eventually admitted to helping her mother poison the family, telling McAmis that Diane wanted her brother “out” and Sarah was “equally unneeded.”
Rachel was arrested the day after her mother. In 2016, Rachel admitted to the murders and attempting to poison Sarah. She was sentenced to two life sentences and twenty years in prison. She’ll be eligible for parole after 42 and a half years in prison.
Diane pleaded guilty to two counts of murder and received a life sentence without the possibility of parole.
Charles Alexander, Mark’s former bandmate, stated that he still thinks about the murders of his friend and son. “We lost,” he told People. “We all lost.”
