Man who allegedly carried knife that said 'Teacher Dear' identified as suspect in teacher’s fatal stabbing

SAN JOSE, Calif. (TCN) -- Investigators recently identified a suspect in the death of a teacher who was found stabbed to death in a school hallway near her classroom almost five decades ago.

According to the Santa Clara County District Attorney’s Office, on June 16, 1978, a student found Diane Peterson on the floor at Branham High School with a stab wound to her chest. Officials determined the stabbing had occurred on the first day of summer break while teachers were cleaning their classrooms.

A student reportedly told his family that he witnessed Harry Nickerson, who was 16 at the time, killing Peterson, but he later denied making the statement. According to the district attorney’s office, in 1984, someone also said Nickerson "implicated himself in the killing, which he said was in response to discovering Nickerson in the act of a drug deal."

Investigators conducted extensive DNA work between 2023 and 2024 but were unsuccessful in obtaining leads.

In a June 2 press release, authorities said they learned that Nickerson allegedly confessed to a family member that he stabbed Peterson, and they officially named him the primary suspect. A witness had also previously informed police that the suspect admitted to the slaying, and he "had seen him carrying a knife that had written on it, 'Teacher Dear.'" However, police couldn’t corroborate the statement at the time.

According to prosecutors, Nickerson fatally shot himself in 1993.

Following Peterson’s death, Nickerson had been arrested and convicted of multiple charges, including armed robbery, assault with a deadly weapon, and kidnapping. In 1984, he was shot while allegedly trying to commit a drug robbery, and no charges were filed.

One of Peterson’s family members reportedly thanked investigators for "not giving up for 47 years," adding, "Diane was a beautiful and wonderful person who is missed dearly."

District Attorney Jeff Rosen 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. I am pleased that we have solved this case, even though the murderer is not alive to face justice. I wish he was."

San Jose Police Chief Paul Joseph stated, "Nearly five decades have passed since a young teacher’s life was tragically taken. 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."

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