Rachel Staudte confessed in her diary to helping her mom poison her father and siblings with antifreeze, one by one, police tell PEOPLE

By KC Baker
October 21, 2016 09:00 AM

As police questioned Rachel Staudte about the mysterious deaths of her father and siblings, she initially denied any involvement.

But a purple diary she kept hidden in her closet told another story.

The truth, Rachel confessed in its pages, was far more chilling — and deadly — than the “picture-perfect” exterior her family showed to the world, staying brave in the face of repeated tragedies.

As police would learn, Rachel worked with her mom, Diane, to poison her father and siblings with antifreeze, one by one. Diane, 54, confessed to authorities that she hated her husband, Mark, and found her other children burdensome.

But such revelations would only come months after Mark, the first Staudte victim, fell dead.

Much later, authorities discovered that what seemed like endless strokes of bad luck for one family in fact went all according to plan.

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Courtesy Staudte Family
Courtesy Staudte Family

The Staudtes Start Feeling Sick

Back in 2012, life seemed to be going well for Rachel, a straight-A student and budding artist, who often showed off her drawings and paintings on Facebook.

She also played the flute, performing with Diane, the longtime organist at Redeemer Lutheran Church in quiet Springfield, Missouri.

Those who knew Rachel, her parents and three siblings said they seemed happy and normal. In fact, as her dad’s friend and band mate Rob Mancuso tells PEOPLE in this week’s issue, “They seemed like a picture-perfect family.”

That seemingly idyllic life began to fall apart on April 8, 2012 — Easter Sunday — when Mark, a 61-year-old stay-at-home dad, died of what the medical examiner ruled natural causes.

Mark had complained of flu-like symptoms in the days leading up to his death and had worried fellow band member Charles Alexander by showing up at his house the day before he died, barely able to stand and with a yellow tint to his skin, Alexander tells PEOPLE.

“He was so young,” says Cindy Mancuso, Rob’s wife.

Friends thought it was odd that Rachel, who posted frequently on Facebook, didn’t mention her father’s death, instead posting a poem by Goethe, “Wayfarer’s Night Song II.”

Five months later, the family was hit again. On Sept. 2, 2012, Rachel’s older brother, Shaun, who Diane told authorities had suffered from seizures, died on the floor of his room from what the medical examiner ruled prior medical causes.

Like his father, 26-year-old Shaun, who had a mild form of autism, had complained of flu-like symptoms before he died.

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Friends of the family say they thought it was strange — once again — that Rachel failed to mention her brother’s death on Facebook. She also ignored the fact that the following June, her older sister, Sarah, then 24, was admitted to the hospital with flu-like symptoms that turned out to be organ failure.

Police were later tipped off to what was really going on by the family’s suspicious pastor. But they didn’t think Rachel had anything to do with the deaths.

Then, Springfield police detective Neal McAmis tells PEOPLE, he decided to ask Diane.

Photos of Diane and Rachel Staudte from her Facebook account

‘Rachel Wouldn’t Hurt a Fly’

McAmis says Diane had repeatedly praised Rachel, her second-youngest child, during her own questioning in the family’s deaths.

“I had no knowledge whatsoever about Rachel,” McAmis says. “But given the way [Diane] was talking about Rachel — she would light up when she would talk about Rachel — I actually asked her, ‘Was she involved?’ ”

“Of course [Diane] denied it,” he says. “I think she said something like, ‘Rachel wouldn’t hurt a fly.’ ”

But while McAmis interrogated Diane, detectives searching the Staudte house found a purple diary hidden in Rachel’s closet.

According to court records, inside was an eerily prophetic entry dated June 13, 2011 — a year before Mark died — that read: “It’s sad when I realized how my father will pass on in the next two months … Shaun, my brother will move on shortly after.”

“It will be tough getting used to the changes,” the entry read, “but everything will work out.”

Rachel also wrote that she was pleased she had time to prepare for their deaths, and that she would be getting “dad’s car.”

When McAmis asked Diane about the journal entry, he says “she acknowledged that Rachel had written that down but said that Rachel had just had a dream that Mark and Shaun had died and chronicled that in a journal.”

Rachel said the same thing when questioned, McAmis says. But just like her mom, her story “started crumbling” and she confessed.

Women’s Eastern Reception Diagnostic orrectional Center
Women's Eastern Reception Diagnostic orrectional Center

‘I Didn’t Want Another One to Die in the House’

While Rachel told detective McAmis she had agreed to help poison her father, she said that she was hesitant to poison her brother and sister, according to transcripts of the interrogation.

“Shaun we argued on a lot because I still think we could have put him in an assisted living, but she wanted him out,” Rachel told McAmis, according to the transcript. “Sarah was equally unneeded. We could have found some place else for her. [Diane] was very adamant that Sarah was just a burden.”

McAmis says he was shocked when Rachel told him that she and her mother took Sarah to the hospital only because Rachel worried about the stench that would linger in the house if she died.

“I didn’t want another one to die in the house,” she told McAmis, according to the transcript, “because houses are nasty after somebody’s died in it.”

Shaun’s death, she said, also left her with “a lot of nightmares,” she told McAmis: “After Shaun died, I moved into his room and it was awful, awful, awful in there. I kept feeling things in there. I just didn’t want that again.”

McAmis says Rachel “stunned” him when she admitted that she and her mother also planned to eventually poison her youngest sister, Brianna, who was then 11.

“I know there’s no way in hell I’d be able to take care of her,” she told McAmis by way of explanation. “I can’t take care of me, so how could I ever take care of her?”

Rachel was arrested on June 2013, just like her mom, and charged with two counts of first-degree murder and one count of assault.

Diane was sentenced earlier this year and is serving a life sentence without parole for first-degree murder and first-degree assault. (She entered an Alford plea, which acknowledges that prosecutors had enough evidence to convict her without admitting guilt.)

In March 2015, Rachel, now 25, pleaded guilty to second-degree murder in exchange for agreeing to testify against her mother if she ever went to trial. Rachel was sentenced to two life prison terms plus 20 years, but she will be eligible for parole after 42 years.

Both Diane and Rachel have filed motions asking a judge to vacate their pleas. Prosecutors and defenders for Diane and Rachel declined to comment, since the motions are still pending.

Looking back, McAmis says that while he has seen a lot in his 16-plus years in law enforcement, he will always remember this case.

“Just when I thought this couldn’t be more bizarre, something else popped up,” he tells PEOPLE. “There was always another curve ball that seemed to be coming.”