Student found teacher dead near classroom in 1978, CA officials say. Now, closure
Decades after a student found a teacher stabbed to death near her classroom the day after summer break began, the accused killer in her slaying has been identified, California prosecutors say.
Thanks to an interview this year, Harry “Nicky” Nickerson, who was 16 at the time of the fatal stabbing and died in 1993, was identified as the suspect in Diane Peterson’s 1978 killing, the Santa Clara County District Attorney’s Office said in a June 2 news release.
“Nearly five decades have passed since a young teacher’s life was tragically taken,” San Jose Police Chief Paul Joseph said in the release. “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.”
Student finds teacher dead
The day after summer break began, “a student found Peterson lying on the floor near her classroom with a single stab wound to her chest” at Branham High School on June 16, 1978, prosecutors said.
When Peterson was fatally stabbed, she, like other teachers at the school, was cleaning her classroom for the upcoming break, according to prosecutors.
At the time, Nickerson was a suspect in her killing, prosecutors said.
A booking photo taken of Nickerson just days after the slaying “bore a strong similarity to a composite sketch based on eyewitness accounts of the attack,” prosecutors said.
Five years later, a family of a student came to San Jose police saying their son saw the killing and identified Nickerson as a suspect, prosecutors said.
Later, however, the student denied his claim, prosecutors said.
In 1984, a witness told police that “Nickerson implicated himself in the killing, which he said was in response to discovering Nickerson in the act of a drug deal,” according to prosecutors.
A witness also told police Nickerson confessed to the slaying and that he saw “him carrying a knife that had written on it: ‘Teacher Dear,’” something police were not able to confirm at the time, prosecutors said.
For decades, the case remained stagnant, and a suspect in Peterson’s killing was never charged.
Confession unearthed decades later
In 2023 and 2024, prosecutors said the district attorney’s crime lab looked to DNA testing to close the case.
However, such attempts failed, prosecutors said.
Instead, it was an interview with Nickerson’s family member in 2025 that “broke the case,” prosecutors said.
As police investigators spoke with the family member, they told them “Nickerson came to their home minutes after the killing and confessed to having stabbed Peterson,” prosecutors said.
Nickerson went on to be convicted in a string of crimes, including “armed robbery, assault with a deadly weapon, and kidnapping,” prosecutors said.
He died by suicide in 1993, prosecutors said.
“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,” District Attorney Jeff Rosen said in the release. “I am pleased that we have solved this case, even though the murderer is not alive to face justice. I wish he was.”
Upon closing Peterson’s case, one of her family members told investigators “Diane was a beautiful and wonderful person who is missed dearly.”
This story was originally published June 3, 2025 at 11:50 AM with the headline "Student found teacher dead near classroom in 1978, CA officials say. Now, closure."
