When investigators in Santa Clara County reopened the chilling case of a young teacher murdered in 1978, they didn’t just find a resolution, but rather uncovered a haunting piece of California’s past. The victim, Diane Peterson, a 26-year-old English teacher at Branham High School in San Jose, was found brutally stabbed in a school hallway days after summer break had begun. The episode shocked the community, but despite early leads, it went cold for nearly half a century… until now.
According to the Santa Clara County District Attorney’s Office, the breakthrough came in early 2025, when a relative of Harry “Nicky” Nickerson, a former student of Ms. Peterson, came forward. The family member revealed that Nickerson had confessed to the murder shortly after it had occurred. At the time of the killing, Nickerson was just 16 years of age, and had a troubling history that included being associated with drug dealings, as well as accounts of “carrying a knife that had ‘Teacher Dear’ written on it,” according to a claim made by a witness in the case.
While Nickerson had long been considered a person of interest due to reports of people seeing him near the crime scene, as well as his resemblance to a composite sketch of the murder suspect that was made using descriptions from eyewitnesses, there had never been enough evidence to charge him. Decades later, even after renewed DNA testing findings have been inconclusive, the eyewitness testimony, in combination with historical records, finally gave prosecutors the closure they needed. That said, Nickerson will never face trial, due to the fact that he died by suicide in 1993.
“While the suspect will never stand trial or face the consequences for his actions, we hope this resolution brings a measure of peace to the victim’s loved ones and to a community that has carried this loss for far too long,” said San Jose Police Chief Paul Joseph in a public statement. “Let this serve as a solemn reminder: no matter how much time passes, we will continue to seek the truth—because every victim matters, and every life deserves justice.”
The news has reverberated throughout the San Jose community. Former students and colleagues of Peterson described her as passionate, kind, and devoted to education. For many, the resolution has brought bittersweet relief.
“Diane was a beautiful and wonderful person who is missed dearly,” described a family member of Peterson. They continued by thanking investigators for “not giving up for 47 years.”
Still, the case has reignited conversations about how many other cold cases remain unsolved due to insufficient evidence or outdated forensic methods. Advocates hope that the Peterson case will encourage others with long-buried information to come forward, even decades later.
