Teen Identified As Killer In Decades-Old Cold Case Of Murdered School Teacher

A teacher who was murdered at a California school almost 50 years ago was killed by a 16-year-old boy who carried a knife inscribed with “Teacher Dear,” officials say.

On June 16, 1978, the day after summer break began, Diane Peterson was stabbed once in the chest at Branham High School while cleaning out her office.

The cold case has now been solved after a family member of the killer spoke to investigators, the Santa Clara County District Attorney’s Office said.

Harry ‘Nicky’ Nickerson, who died by suicide in 1993, has now been identified as Peterson’s killer.

This year, investigators spoke to one of Nickerson’s family members, who told them he had come to their house and confessed to the killing just minutes after it happened.

Nickerson had long been a suspect in the murder, after a booking photo of him four days after the attack closely matched a composite sketch based on an eyewitness account.

A witness had told police that Nickerson had confessed to the crime and that he had seen him carrying a knife that was inscribed with “Teacher Dear.” Police at that time were unable to corroborate the claim.

In 1983, the family of a Branham student informed police that their son had witnessed the murder and identified Nickerson as the person responsible.

The student, however, later denied making that statement.

Then, in 1984, a witness told police that Nickerson had implicated himself in the killing and had said it was in response to catching him in the middle of a drug deal.

Extensive DNA work was conducted in 2023 and 2024 in a bid to catch the killer—but with no luck.

San Jose Police Chief Paul Joseph welcomed the development in the case.

“Nearly five decades have passed since a young teacher’s life was tragically taken,” he said.

“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.”

District Attorney Jeff Rosen added: “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.”

In the years following the murder, Nickerson was arrested and convicted of an array of charges, including armed robbery, assault with a deadly weapon, and kidnapping.

He was shot and critically injured in 1984 while attempting to commit a drug robbery, but given the circumstances, no charges were filed.

Nickerson took his own life in 1993.

Peterson’s family has now thanked investigators for “not giving up for 47 years.”

“Diane was a beautiful and wonderful person who is missed dearly,” a relative said.