After 47 years of mystery, the brutal murder of a California high school teacher has finally been solved.
On June 16, 1978, Diane Peterson was found dead at Branham High School in San Jose, California.
She was stabbed in the heart with a knife chillingly inscribed with “Teacher Dear “by a 16-year-old student identified as her killer.
The brutal killing shocked the community, with witnesses reporting they heard Peterson desperately calling for help before seeing someone flee the scene.
“A student at the time heard Diane calling for help. She was saying help, help, help. That student actually saw the perpetrator flee from the scene,” said Santa Clara County Deputy District Attorney Rob Baker.
Despite having multiple suspects and leads, investigators at the time were unable to gather enough evidence to make an arrest.
Harry “Nicky” Nickerson, a 16-year-old student at the school, was identified as the prime suspect.
Witnesses claimed Nickerson had confessed to the murder and was seen with the murder weapon, but police could not corroborate these claims at the time.
A composite sketch based on eyewitness accounts closely resembles a 1978 photo of Nickerson, further pointing to his involvement.
The case went cold despite numerous attempts to solve it. In 1983, a student claimed to have witnessed the murder and identified Nickerson, but later retracted the statement.
The following year, another witness reported that Nickerson had implicated himself, suggesting the murder was related to a drug deal.
Yet the case remained unsolved, allowing Nickerson to escape justice.
The breakthrough finally came when a family member revealed that Nickerson had confessed to the murder shortly after committing it.
“The relative admitted to police that Nickerson came to their home minutes after the killing and confessed to having stabbed Peterson,” officials at the Santa Clara County District Attorney’s Office stated.
Tragically, Nickerson will never face justice for his heinous crime. After a life of violence, including armed robbery, assault, and kidnapping, he died by suicide in 1993.
Before taking his own life, Nickerson sustained a critical injury during a drug robbery in 1984. His death denied Peterson’s family the closure of seeing her killer held accountable in court.
Santa Clara County District Attorney Jeff Rosen expressed both relief and regret:
“This marks the end of a terrible and tragic mystery. Ms. Peterson would have been a senior citizen today if she had not crossed paths with this violent teenager. I wish she was. I am pleased that we have solved this case, even though the murderer is not alive to face justice. I wish he was.”
The District Attorney’s Cold Case Unit has been diligently working to solve long-forgotten crimes. Between 2023 and 2024, extensive DNA testing was conducted in Peterson’s case.
This marks the fourth cold case the DA’s Office has solved this year, with over 30 cases resolved since 2011.
San Jose Police Chief Paul Joseph emphasized the importance of pursuing these cases regardless of how much time has passed:
“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. 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.”
Peterson’s family has expressed gratitude for the investigators’ persistence over nearly five decades.
Although they will never see Nickerson face consequences for his actions, they at least have been allowed to finally close this painful chapter in their history.
