Cold case murder of San Jose teacher solved after 47 years; teen killer had knife inscribed with "Teacher Dear"
Investigators have solved the cold case murder of a San Jose teacher stabbed to death at Branham High School nearly 50 years ago, naming a teenager who was originally suspected in the crime as the killer, authorities announced Monday.
On June 16, 1978, a student found Diane Peterson on the floor near her classroom with a single stab wound to her chest, the day after school was let out for summer and while teachers were cleaning out their classrooms.
Teen suspected early in the case
The Santa Clara County District Attorney's Office that Harry "Nicky" Nickerson, a 16-year-old at the time, was the person who stabbed Peterson. Nickerson had been suspected in the case, and he bore a resemblance to a police sketch of the suspect based on witness accounts. Nickerson was not a student at Branham, Deputy District Attorney Rob Baker said at a press conference Monday.
A witness also told police had told police that Nickerson had confessed to the crime and that he had seen him carrying a knife with the words "Teacher Dear" written on it, the DA's Office said. Police were unable to corroborate the claim, and prosecutors were unable to make the charges stick.
The DA's Office said that in 1983, the family of a Branham student told police that their son claimed to have seen the killing and identified Nickerson as the suspect. The student later denied making that statement.
A year later, another witness told police that Nickerson implicated himself in Peterson's murder, which he said was a result of her discovering him dealing drugs, the DA's Office said.
DNA lab work in cold case, family confession
In 2023 and 2024, the DA's crime lab ran extensive DNA work on the case, but investigators were unable to identify the perpetrator. Earlier this year, however, the investigators learned that years ago, Nickerson had confessed to the killing to a family member. The relative admitted that Nickerson came to their home minutes after the killing and confessed to having been responsible, according to the DA's Office.
At Monday's press conference, Baker said the circumstances of the case had made it challenging to find and identify any forensic evidence to connect Nickerson to the crime.
"There was no sexual assault, it was a single stab wound, the attack happened basically in a public place at the school," said Baker. "Once we determined there wasn't any physical evidence that was going to help us corroborate these claims or identify the killer in this case, the detectives just decided, you know what, we're just going to reach out to the people who were closest to Mr. Nickerson and see if he made any statements to them. See if they have any information to close the loop on this case to try to give answers and closure to the family."
In the years that followed the murder, Nickerson was convicted of a series of crimes, including armed robbery, assault with a deadly weapon, and kidnapping. The DA's Office said Nickerson was shot and critically hurt while attempting a drug robbery in 1984, but no charges were ever filed.
Nickerson died from a self-inflicted gunshot wound in 1993.
"This marks the end of a terrible and tragic mystery," said District Attorney Jeff Rosen in a prepared statement. "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."
"Nearly five decades have passed since a young teacher's life was tragically taken," said San Jose Police Chief Paul Joseph in a statement. "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."
The DA's Office said its cold case unit has solved over 30 cold case murders from as early as 1969 since it was established in 2011, and the Peterson case is the fourth cold case homicide it has solved this year.
A family member of the victim who asked not to be identified thanked investigators for "not giving up for 47 years."
"Diane was a beautiful and wonderful person who is missed dearly," the family member said in a statement.
Editor's note: A previous version of this story said that Nickerson had been a student at Branham High School at the time of the murder. The District Attorney's Office clarified on Monday that Nickerson was not a Branham student.
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