Truth is often uglier than the scripts we see on television. When people search for details on how were the decker girls killed, they are usually looking for the cold, hard facts of a case that shattered a small community in 1986. This wasn’t just a tragedy; it was a brutal, intimate violation of a home that left investigators and neighbors reeling for decades.
In October 1986, in the quiet town of Mount Pleasant, Iowa, the lives of 10-year-old Kelly Decker and 7-year-old Gaelle Decker were extinguished in a way that remains difficult to discuss even now. It wasn't a random act of violence by a passing stranger. It was a targeted, horrific crime committed by someone the family knew—someone who had lived under their roof.
The Night Everything Changed in Mount Pleasant
The Decker family lived a relatively normal life until everything stopped on a Tuesday night. Most people assume there must have been some massive warning sign. Honestly, there rarely is. The girls were at home with their mother, Donna, and a 19-year-old man named Robert "Bobby" Goin. Goin wasn't a stranger; he was a family friend who had been staying with the Deckers.
Basically, the violence started late.
Bobby Goin didn't just snap in a vacuum. He had a history of internal turmoil, but nobody predicted he would turn a knife on two children. The girls were stabbed. It wasn't quick. It wasn't "clean," if such a thing exists. They were attacked in their own home, a place that should have been their ultimate sanctuary. Gaelle and Kelly suffered multiple stab wounds during the assault, which also targeted their mother.
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Why the motive remains so chilling
What makes the question of how were the decker girls killed so haunting isn't just the physical act—it’s the "why." Or rather, the lack of a "good" why. Goin apparently became enraged over a perceived slight or a rejection from Donna Decker. When he couldn't control the mother, he turned his inexplicable rage toward the most vulnerable people in the house: her daughters.
The sheer level of overkill in the stabbings suggested a deep-seated resentment. It wasn't a robbery gone wrong. It was a massacre fueled by a young man's inability to process his own emotions. He used a knife from the kitchen. It’s that mundane detail that usually sticks with people—the idea that a common household tool was used to end the lives of two little girls who were likely just getting ready for bed or sleeping.
The Aftermath and the Arrest of Robert Goin
Donna Decker survived. She was the one who had to bear the physical and psychological scars of that night while identifying the man who murdered her children. Goin fled the scene but didn't get far. The Iowa Division of Criminal Investigation (DCI) and local police moved fast. They found him relatively quickly, and the evidence was overwhelming.
He was eventually convicted of two counts of first-degree murder and one count of attempted murder.
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I think it's important to realize how much this case changed Iowa's perception of safety. Before 1986, Mount Pleasant was the kind of place where you didn't lock your doors. After the Decker girls were killed, that changed. People realized that the "monster" wasn't always a drifter under a bridge. Sometimes, it was the guy you let sleep on your couch because he had nowhere else to go.
Legal technicalities and the long road to justice
Goin was sentenced to life in prison without the possibility of parole. In Iowa, a life sentence actually means life. There have been various appeals over the years—standard stuff for high-profile murders—but the evidence remained airtight. The autopsy reports, which I won't detail here out of respect for the family’s privacy, were reportedly so graphic that they deeply affected the jurors who had to view them.
The prosecution focused heavily on the premeditation aspect. Goin didn't just bump into them; he sought them out. This distinction is what moved the case from second-degree to first-degree murder.
Why We Still Talk About the Decker Girls
Social media and true crime podcasts have a way of digging up these "cold" cases, even though this one was solved decades ago. People are fascinated by the psychology of the offender. How does a 19-year-old decide to kill two children?
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- The age of the victims (7 and 10) creates a visceral reaction.
- The betrayal of trust is the central theme.
- The survival of the mother adds a layer of "final girl" tragedy that feels like a movie, but was a painful reality.
Honestly, the Decker case serves as a grim reminder of the "proximity" rule in violent crime. Statistically, you are far more likely to be harmed by someone you know than by a masked intruder. Kelly and Gaelle weren't victims of a home invasion; they were victims of a houseguest.
Moving Beyond the Tragedy
For those following this case or researching how were the decker girls killed, the most important takeaway isn't the gore. It’s the legacy of the girls and the importance of recognizing red flags in domestic situations. Bobby Goin had shown signs of instability and possessiveness before the night of the murders.
If you are looking for ways to honor the memory of victims like the Decker girls, or if you find yourself in a situation where a domestic dynamic feels unsafe, there are specific steps to take.
Actionable Steps for Safety and Awareness
- Trust your gut on "houseguests." If someone staying in your home makes you or your children feel even slightly "off," prioritize that feeling over being polite.
- Support Child Advocacy Centers. Organizations that work with survivors of domestic violence and child abuse often operate on shoestring budgets. Donating to groups like the National Center for Missing & Exploited Children or local Iowa-based advocacy groups helps keep resources available for families in crisis.
- Learn the signs of escalating domestic behavior. Often, violence against children starts as control or violence against a parent. Organizations like the National Domestic Violence Hotline offer resources on how to identify these patterns before they turn fatal.
- Advocate for mental health resources. While it doesn't excuse his actions, Goin's age and history suggest a massive failure in the mental health net. Supporting early intervention programs for troubled youth can prevent future tragedies.
The Decker girls are buried in Forest Home Cemetery. Their headstone is a quiet place now, a far cry from the chaos of that night in 1986. While the world remembers how they died, the community of Mount Pleasant tries to remember how they lived—as two sisters who deserved a much longer story than the one that ended on a kitchen floor.