The Revisionist History of Poisoner Diane Staudte

Think Wisdom (or Remorse) Comes with Age? Apparently Not for this Female Serial Killer

If you haven't watched the February 25 episode of 20/20, promise me you will. It is an interview with Diane Staudte, who is currently serving life without parole in a Missouri prison. Her daughter, Rachel - now in her early thirties - is doing life. Rachel will have a slim chance at parole when she is sixty-two. If she is successful, she will be one year older than her father was when he was poisoned with antifreeze by this mother-daughter duo. He wasn't their only victim.

Here's your second "assignment." After watching the 2/25/2022 episode, go on Youtube and watch Rachel and Diane's original interrogation videos. Quite a different story this time around, right?

Staudte's Start Dying

Here's what came out during the initial police investigation: On June 13, 2011, twenty-two-year-old Rachel Staudte wrote these words in her diary.

"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, but everything will work out."

Fifteen months later, both were dead. They died 147 days apart.

The family of six was now a family of four. Then, in June 2013, lightning struck again. Rachel's twenty-four-year-old sister, Sarah, was admitted to the hospital. What started as flu-like symptoms — nausea, chills, diarrhea, headache, body aches — quickly worsened. By the time Diane took Sarah to the emergency room, her organs were failing. She was in bad shape.

What the hell was going on? Doctors were stumped. They tested her for many illnesses that caused similar symptoms; all were negative. If they couldn't figure out what was wrong, Sarah could die.

Nurses were also puzzled, not only by the young woman's mysterious illness but also by her mother's bizarre behavior while visiting her. Her daughter was at death's door while fifty-four-year-old Diane Staudte joked with the medical staff and talked about the Florida vacation she had planned for the following week. But it was an anonymous tip that got the wheels of justice rolling towards Diana.

Let's Kill Off the Dead Weight

We don't know when Diane Staudte first talked to her daughter Rachel about teaming up to murder the rest of their family. We do know they talked about it at length and a lot. And, at some point, pondering turned into planning.

The two did quite a bit of research. They considered suffocation. They thought about combining various pills/medications into a lethal combination. Then they realized antifreeze would be simpler. However, because the kind sold in stores had a bitter taste, they bought an odorless, tasteless version from the internet. It was easy to slip it into favorite drinks; Mark's Gatorade and Shawn's and Sara's sodas.

At first, sixty-one-year-old Mark was the only target. Diane later told investigators that she hated her stay-at-home husband, who didn't have a regular job and sometimes "threw things" at her and the kids. Rachel didn't personally have a problem with her dad but wanted to help relieve her mother's stress and unhappiness. And the $20,000 she received in life insurance certainly seemed to lift Diane's spirits. They even moved into a bigger house.

However, Mark's murder must have sparked something in Diane because he barely had one foot in the grave before she plotted to kill their twenty-six-year-old son, Shaun. Shaun had autism and a seizure disorder and, as such, was unable to live independently. But this doesn't appear to be what sealed Shaun's fate. It was his "annoying" personality. To his mother, Diane, Shaun was "worse than a pest."

Rachel claims she argued with her mother about killing Shaun. "I thought we could put Shaun in an assisted living facility or something, but Mom was definite that he had to go." But she was overruled. In September 2012, after suffering symptoms for three weeks with symptoms very similar to his father's, Shaun died. No one suspected a thing.

Diane and Rachel waited until June 2013 to poison Sarah. The motive? They thought she was lazy. She wasn't making an effort to get a job. She sat around watching YouTube videos without lifting a finger around the house. Diane had been the sole breadwinner for years, and she was tired of it. And she sure wasn't going to pay Sarah's student loans.

Plus, Rachel told investigators, "She's nosy. Very nosy."

If Sarah had died, would that have been the end of it? There was still twelve-year-old Brianna. Diane said that she didn't kill her two youngest children because she loved them and they weren't a burden to her. But that's not the story Rachel gave the police. She told them she and her mom had already decided to kill Brianna, who had a learning disability and needed extra help at school, because Diane didn't want the responsibility. As for Rachel, "I can't take care of her. I can't even take care of myself."

The Cult of Two

In Diane's 2013 interrogation interview, her animosity towards her targeted family members oozes through the camera. Not so with Rachel, who seems to parrot her mother's complaints. Diane may have been motivated by anger, but Rachel appears to be inspired by love. Rachel adored her mother. In the interrogation, she seems seduced by the fantasy of having her mom to herself, just Diane and her golden child living happily ever after.

Rachel had a lot going for her. She excelled in school, was a talented artist, and spoke four languages. Each of her siblings struggled. Perhaps it's not surprising that Diane would take special pride in Rachel.

And she did. Rachel's Facebook account was filled with her mother's encouragement and praise. "Congrats! Dean's list once again." "Just think, next week, by this time, you will be done for the semester!" "Nice job reading tonight." Diane's Facebook page has pictures of Rachel, photos of her artwork, and numerous playful and affectionate back and forths between Diane and Rachel. There is barely a mention of the rest of her family.

But there's a big difference between having a favorite child and plotting to make her the only one.

The Mask Diane Hid Behind

Everyone who knew Diane Staudte was stunned when she confessed. Is Diane capable of murder? Surely not.

If anything, friends saw Diane as something of a martyr, a devout Christian mom who sacrificed her own wants and needs for her family. She had a lot on her shoulders, working full time as a clinical supervisor with UnitedHealthcare while playing the organ at the Lutheran church and raising four children. Her Facebook posts were filled with religious sayings, inspirational quotes, and prayer requests.

We don't know what went on inside Diane's head. She and Mark were married for twenty-six years. His friends seemed to think Mark was a happy husband and devoted father. He had joined a local band in the fall of 2011 and seemed to be enjoying his role as lead vocalist and guitar player. He picked up an occasional bartending shift and looked after Brianna.

Their children seemed to think Diane was a normal if somewhat stressed, mom. Sarah knew her mom wanted her to get a job and was frustrated that she was back at home with student loans that needed to be paid. But she never dreamed her mom would hurt her, even after reading her mom's journal entry foretelling her death.

Diane had everyone fooled. No one except Rachel had any idea of the rage and frustration lurking beneath her mother's façade. Even when confessing, there was little evidence that Diane felt any genuine remorse or regret for what she had done. There was also little evidence of love.

Did she even love Rachel? Diane certainly loved what Rachel gave her — adulation, sympathy, the image of a successful parent. But it's hard to imagine a loving parent grooming a child to be your partner-in-crime, especially when the victims are your family. Diane seemed more than willing to risk sacrificing Rachel's future to get what she wanted.

It's Hard to Pretend All the Time

As a forensic psychologist, I spend a lot of time evaluating people who have a lot to lose and plenty of reasons to lie. If you've killed someone, the evidence is overwhelmingly against you, and your life is at stake, it's understandable why someone might try to fake insanity.

On the flip side, if you've been committed to a forensic psychiatric hospital and you're dying to get out, you might do everything in your power to hide your mental health symptoms. No judgment on my part.

But here's the thing. Even the most devious among us can't pretend all the time. Sure, someone can fake me out for a few hours, but you can bet I will be talking to the custody officers, nurses, and other people around them 24/7. I will be reading police reports, witness statements, jail records, and treatment notes. And that's what helps me get to the truth.

No one — not police or medical professionals or friends or family — thought that Diane was responsible for foul play, not even when the third family member was at death's door in a year. Until they noticed how Diane was acting. This is how Diane shot herself in the foot.

When visiting Sarah, nurses noticed how uncaring (and downright jovial) Diane seemed. Mark's friends noticed a distinct lack of grief at his funeral. Shawn's uncle didn't find out about his nephew's death until weeks after he died. And, even then, it was from another relative.

And the anonymous tipster? It turned out it was Diane's pastor. He's spent hours consoling grieving families, and he was struck by Diane's lack of emotion when her husband and son died. But it was when, while spending hours volunteering as the church's organist, she never mentioned to him that her daughter was in the hospital fighting for her life that he picked up the phone and called the police.

Still Faking After All These Years

I don't know what I was hoping for when I watched the 20/20 interview. I thought perhaps Diane had gotten some perspective on why she made her choices; Lord knows, she's had years to think about it. I thought she might have embraced religion in the fervent way lifers sometimes do. I even held out faint hope that she would express remorse, if not for the family members she killed, at least for the tarnished life left to her Golden Child, Rachel.

Given her detailed 2016 confession and plea deal, it never occurred to me that Diane would be spinning a different yarn, one in which she was a victim of a vague conspiracy that possibly involved herself also being poisoned and in which threats from an unnamed menace forced her to admit guilt. A few weeks later, I saw a similar performance by another husband poisoner.

I should have known better. I remember the absolute dog fight over Roger Keith Coleman's death sentence. Coleman was convicted for the 1981 rape, torture, and murder of his wife's sister, nineteen-year-old Wanda McCoy. Even though there was a ton of circumstantial evidence against him, he proclaimed his innocence for years. He convinced thousands of people of his innocence; one of them, the executive director of Centurian Ministries, fought tooth and nail for his exoneration for four years and shared Coleman's last meal.

Here's what Coleman himself said before he was executed on May 20, 1992:

"An innocent man is going to be murdered tonight. When my innocence is proven, I hope America will realize the injustice of the death penalty as all other civilized countries have."

In 2006, the Governor of Virginia settled this issue once and for all. He ordered now-available DNA testing on material left at the crime scene. You've got to admit; that takes some guts. Think of the outrage that would have followed if Colemen had been innocent.

But he wasn't. In fact, the report from the Centre of Forensic Sciences in Toronto stated that the sperm found in the victim was a match. "The probability that a randomly selected individual unrelated to Roger Coleman would coincidentally share the observed DNA profile is estimated to be 1 in 19 million," the report said.

The Bottom Line

Innocent people do get convicted. We have to do everything we can to make damn sure they don't. There are also people as guilty as Cain who create a story that fits the reality they want instead of the reality there is. And that's not innocence; that's lying.

Thanks for reading! Please share with your true crime buddies. See you next time.