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DR. JONI JOHNSTON is a Forensic Psychologist, Private Investigator, and Crime Writer. 


As a practicing psychologist, she has worked in a medium-maximum security prison, for the Board of Parole, for the Superior Court of San Diego, and as a workplace investigator of misconduct allegations including harassment, discrimination and violence.


She currently evaluates mentally disordered offenders up for parole as provides expert testimony in criminal and civil litigation where a forensic psychologist can help shed light on pertinent issues.



I've always been interested in understanding the criminal mind. It's why I became a forensic psychologist. Today, my job is to provide insight in areas where law and psychology intersect - when a mentally ill defendant commits a crime, when a disgruntled employee threatens violence, when a violent offender is about to be released on parole. You might find me testifying as an expert witness, evaluating an inmate in a maximum security prison, or investigating a harassment complaint.         

But forensic psychology applies to more than just the courtroom; it touches all of us. That's why it's important to me to share what I learn with the general public, through my Psychology Today blog (Human Equation), as a contributing writer for True Crime: Case Files Magazine, as a consultant on true crime shows, and through my books (such as The Complete Idiot's Guide for Psychology). We all know knowledge is power. When it comes to understanding the criminal mind, knowledge can mean the difference between life and death.


Mental Illness and Violence

Thepsychotic killer may make a great Halloween costume, but in real life, they're suprisingly rare.

Why is Someone Burning Homeless Men in San Diego?

A serial killer in San Diego is setting fire to homeless men. Why?


Have You Ever Wished Someone Was Dead?

Many of us have wished someone would die or disappear when we're angry. BUt how common is it to actually fantasize about committing murder?


Dangerous Lies


Are there some secrets worth killing for? For two men leading double lives, the answer was yes.


"Let's Pretend You're Sick"

The psyche of parents who fake their child's illness.