How a Mother’s Lack of Grief Exposed a Twisted Family Secret

Rob Mancuso wasn’t sure what to make of Diane Staudte’s demeanor after her husband died.

Mark Staudte, 61, of Springfield, Mo., died on Easter Sunday in 2012, after experiencing flu-like symptoms for several days.

During a gathering after his memorial service, Diane acted “like she was hosting a party,” Mancuso told PEOPLE previously about his longtime friend and bandmate. “There was no sadness. I thought it was just her way of grieving.”

Five months later, it seemed like the family was hit with more bad luck when the couple’s son, Shaun, 26, died. Like Mark, he’d had flu-like symptoms before he died. But the medical examiner ruled that Shaun died due to prior medical causes because of the seizures he had suffered.

Diane seemed almost indifferent to her son’s death. “We found out he died from another relative,” Mark’s brother Michael Staudte told PEOPLE, noting that Diane didn’t hold a memorial service for Shaun.

Related: How a Mom’s Horrifying Scheme to Poison Husband and Kids Was Revealed — Thanks to Her Pastor

Even more darkness befell the family the following June, when Diane’s daughter Sarah, then 24, was admitted to the hospital with flu-like symptoms that doctors diagnosed as organ failure.

While Sarah was fighting for her life, an anonymous tipster called police saying he believed Diane had murdered her husband and son.

The caller, later identified as the pastor of Diane’s church, told Springfield police detective Neal McAmis that he, too, had noticed how blasé Diane seemed after the back-to-back deaths in her immediate family.

“He talked about Diane’s lack of emotion when Mark died,” McAmis told PEOPLE. “He thought Diane’s reaction after Mark died was odd.”

Related: Murder by Antifreeze: How a Mother and Daughter Plotted to Kill Their Family Members – One at a Time

The pastor said his suspicions were aroused when Shaun, who seemed healthy, died, and Diane seemed unfazed by it.

During questioning by police, Diane originally denied having anything to do with Mark or Shaun’s deaths. But as her story began to unravel, according to transcripts of the interrogation, she blurted out, “To put it really short and sweet, I knew they were drinking antifreeze.”

When McAmis asked her if she gave it to them, she said, “I didn’t know what else to do.” She said she poisoned Mark over three days by putting antifreeze in his Gatorade, refusing to take him to the hospital “because by then I hated his guts.”

Calling Shaun “more than a bother,” Diane told McAmis she was angry at him because he didn’t work.

She said she was mad at Sarah because she had college loans coming due but had no job.

Diane said she put “a couple of teaspoons” of antifreeze in their drinks because “they would do whatever they wanted to do and never helped.”

On June 21, 2013, Diane was arrested and charged with murdering her husband and son, and trying to kill Sarah.

A Macabre Twist to the Story

While Diane was being questioned, detectives obtained a search warrant for her house where they found antifreeze, soda — and a journal belonging to Diane’s favorite child, Rachel.

What they read inside was horrifying. “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,” one passage read.

Rachel initially claimed she was simply describing her dreams. But she ultimately confessed to helping her mother poison the family, telling McAmis that Diane wanted her brother “out” and that Sarah was “equally unneeded.”

Rachel was arrested the day after her mother. In 2016, Rachel pleaded guilty to the murders and trying to poison Sarah. She was sentenced to two life sentences plus 20 years in prison. She will be eligible for parole after 42-and-a-half years in prison.

Related: Inside a Daughter’s Diary Confessions as She Helped Mom Secretly Poison Dad and Siblings

Diane pleaded guilty to two counts of murder and was sentenced to life in prison without the possibility of parole.

Mark’s former bandmate Charles Alexander said he still thinks about the murders of his friend and his son. “We lost,” he told PEOPLE. “We all lost.”

Read the original article on People