Beyond the Archives: Understanding Why People Commit Crimes to Empower Interventions
Dr. Joni Johnston a Forensic Psychologist Shares Her Views on Crime, True Crime, and Where We Need to Change Policy
This month, we are delighted to share our chat with
in our Beyond the Archives series. Dr. Johnston is a forensic psychologist, private investigator, and true crime writer. She helps evaluate criminals and perpetrators and works with victims. She has also published a book about true crime.
Dr. Johnstons’s substack, The Mind Detective, uses crimes as case studies to explore broader issues, theories, and ideas in forensic psychology. One remarkable aspect of her work is her dedication to identifying areas where policy can be improved.
She also has an excellent YouTube channel.
CC: What sparked your interest in your field of study? Was there anything specific?
I was a true crime follower long before I became a forensic psychologist. I come from a line of true crime followers, actually. My mom was an avid watcher of old-timey crime shows like Mannix, Ironside, and Hawaii Five-O. We even took a side trip on vacation once to see a house where a family had been murdered—the Clutter house in Kansas, from 'In Cold Blood.'
But I might have stayed just a true crime fan if a couple of things hadn't happened. When I was 14, I read "Helter Skelter," and I simply could not understand why somebody would be interested in killing people who had never done anything to harm them. That was mind-boggling to me. I became really interested in trying to understand what we call the criminal mind. Then came Ted Bundy.
When I was a senior in high school, Ted Bundy escaped from a Colorado jail and made his way to FSU, which was about 80 miles from my house. I was about the same age as some of his victims and, with my long dark hair parted down the middle, looked a lot like them a lot. That experience of watching the aftermath of his rampage at the Chi Omega sorority house—two young women murdered, three others brutally attacked in their beds—and hearing the families talk, really turned me from a true crime fan into somebody who wanted to study this field and try to prevent these kinds of crimes from occurring.
CC: Why Substack?
I love to write. I don't have a lot of formal training in writing, but it's something I really enjoy. I also really enjoy talking about forensic psychology—understanding crimes, victims, advocacy—to people who aren't professionals. I thought Substack would be a really good format for that kind of discussion.
I try to use true crime stories as a starting point to explore the bigger questions: What combination of factors turns someone violent? Which intervention points did we miss? I break down complex psychological concepts into understandable insights—the kind of analysis that helps readers recognize warning signs in their own communities.
CC: What do you hope to achieve here?
I hope to use true crime stories as a beginning to talk about bigger picture issues—both in terms of understanding why people wind up doing horrible things and how we can prevent those things from happening. I want to explore the things that happen along the way that steer people down the wrong path, and also how we can empower people to say something, to do something, to speak up when they see things that aren't right.
I also want to advocate more for victims because victims' families are often re-victimized by law enforcement and the criminal justice system. There are a lot of goals, but if I can make a small drop in that pond, I would be very happy.
CC: How do you balance storytelling with academic rigor when publishing?
I try to incorporate research into the stories I tell and stay up to date as much as possible to make sure I'm providing accurate information. The storytelling aspect helps make complex psychological concepts accessible, but I always ground it in solid research and evidence-based understanding.
CC: Briefly tell us what you study and, in your opinion, what is the most pressing issue or the most intriguing unanswered question in your field.
I work with violent offenders every week, and one of the biggest challenges is how complicated these issues are. For every person I evaluate who has committed a violent crime, we can find people who had similar life experiences and who didn't wind up there. Trying to tease out those differences and unravel that puzzle is such a challenge.
The other huge challenge is how do we get more focus on trauma, the things that happen to people that aren't as dramatic or newsworthy as serial murder or murder for hire. The prevention aspect is particularly challenging to secure funding for, and yet that's where the long-term changes occur.
CC: Why do you think it matters today?
It has always been important for us to understand human nature and the factors that influence us - the situational stressors, genetic predispositions, and personality traits – starting with ourselves.
But another huge challenge is that we don't spend enough time teaching kids basic psychological skills: coping mechanisms, ways to handle stress, ways to manage emotions, ways to deal with bad things that happen. We could do a much better job in our school system of teaching emotional intelligence, teaching people how to handle bullying, and teaching people not to bully. There's so much work to be done.
CC: What's the most surprising or counterintuitive thing you've learned in your research?
I've been really lucky to work both with perpetrators and with victims, and what I find counterintuitive is that there's no such thing as a born killer. And there's no such thing as a born victim either. I don't think anatomy is destiny. There is always a point of potential intervention.
CC: If the public could grasp just one key idea about crime and justice, what would it be and why?
The truth behind a crime is seldom as simple as it first appears. Behind every act of violence is a psychological narrative, a motive often hidden beneath layers of shame, rage, delusion, or pretense. Grasping this complexity is essential not just for solving crimes, but for preventing them.
CC: You must encounter many dark, disturbing, and challenging materials during your research. How do you deal with this work?
The nature of forensic psychology actually provides some built-in emotional protection. Unlike therapists who work with clients long-term, I typically see alleged or convicted offenders for specific legal assessments—evaluating violence risk, determining suitability for parole, or assessing criminal responsibility. This focused, time-limited interaction helps me maintain professional distance. I'm there to answer a specific legal question, which gives me a clear framework and purpose.
That said, working with victims' families is entirely different and much more emotionally challenging. They're still seeking justice, still processing trauma, and their pain is raw and immediate. I've worked with several families whose loved one's death was immediately ruled a suicide despite evidence it was a murder. That's the work that stays with me.
I cope in two main ways: First, I channel those feelings into advocacy work, which gives me a sense of purpose and agency in the face of tragedy. When I can use my expertise to push for better policies or support services, it feels like I'm honoring the victims' experiences. Second, I exercise—a lot.
CC: Is there a danger that others may misconstrue the desire to explain why people commit such crimes as justifying them?
Understanding is not excusing. When we identify factors like childhood trauma, neurological differences, or social circumstances that contribute to criminal behavior, we're mapping the pathway, not providing a permission slip. I often use the medical analogy; understanding how cancer develops doesn't mean we're saying cancer is acceptable. We need to understand causation to prevent and intervene effectively.
CC: What are the implications of explaining why people commit such heinous acts?
On one level, it challenges our comfortable notion of 'good' and 'evil' and forces us to consider that under certain circumstances, many people could be capable of terrible acts. But more importantly, it points us toward prevention. If we understand that certain combinations of factors—untreated mental illness, substance abuse, social isolation, past victimization—increase risk, we can intervene earlier. It also has implications for victim support, helping them understand that the crime wasn't their fault and sometimes helping them make sense of senseless acts.
CC: Do these explanations help governments prevent similar acts?
We've seen success with evidence-based programs; early intervention for at-risk youth, trauma-informed approaches in schools, and specialized treatment for individuals showing concerning behaviors before they escalate. The challenge is that prevention requires long-term investment and doesn't make headlines like tough-on-crime policies do.
CC: What about the rehabilitation of perpetrators?
Rehabilitation isn't about being 'soft on crime'; it's about public safety. A person who receives proper services while incarcerated, whether it’s substance abuse treatment, mental health services, or educational opportunities, is far less likely to reoffend. However, treatment must be coupled with accountability. The most effective programs combine therapeutic intervention with restorative justice practices, where offenders must face the impact of their actions while also addressing their underlying issues.
CC: What books, films, or documentaries would you recommend for someone looking to understand your field better?
For books, I'd recommend:
"Mindhunter" by John Douglas & Mark Olshaker—a foundational text on FBI profiling
"The Stranger Beside Me" by Ann Rule—the second true crime book I ever read and still one of my favorites because Ann Rule worked on a crisis line with Ted Bundy before anyone knew he was a killer
"People Who Eat Darkness" by Richard Lloyd Parry—a fascinating book with themes of missing persons, secrets and sociopathy with an international flair
"If You Tell" by Gregg Olsen—a dark tale of familial abuse, manipulation, and staged crime scenes
For documentaries:
"The Jinx: The Life and Deaths of Robert Durst" (HBO)—a chilling exploration of how a wealthy man evaded justice for years
"Evil Genius" (Netflix)—blends bizarre, manipulative psychology with calculated planning
"Don't F**k With Cats" (Netflix)—I confess that few things bring me more satisfaction than seeing the tables turned on an animal abuser.
CC: Our readers would find your work valuable. Could you recommend 2-3 of your posts?
My most recent post, "Matthew Coleman and the Psychology of Conspiracy-Driven Murder," explores the psychology behind conspiracy theories. I examine how someone goes from being a loving father researching online to distorting those theories into violent and bizarre delusions. I try to trace that progression step by step, using established research on conspiracy thinking and violence. I used a pretty disturbing case as the backdrop, so it's not for the faint of heart, but I've gotten great feedback on it, and I'm proud of the psychological analysis.
A couple of other popular posts have been about Bryan Kohberger, the 28-year-old criminal justice graduate student who murdered four University of Idaho college students, and "The Teenage Family Annihilator." Both posts explore the psychological factors that drive seemingly ordinary people to commit extraordinary violence.
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