Calif. teacher’s killing was a mystery for 47 years. Disclosure from relative of student solves it

After decades of suspicion, police in San Jose have confirmed that the killer of a high school teacher in San Jose was a student who was seen with a knife that had the words “Teacher Dear” written on its side.

On June 16, 1978, one day after Branham High School recessed for summer, a student found Diane Peterson lying on the floor of the hallway near her classroom with a single stab wound to her chest, according to the Santa Clara County district attorney’s office.

Peterson was said to be one of several teachers on campus cleaning out their classrooms for the summer break when she was killed, according to the news release.

Image of Diane Peterson. Photo courtesy of the Peterson family.

(County of Santa Clara)

For years, authorities had considered Harry “Nicky” Nickerson, at the time a 16-year-old student at the school, as a person of interest in the case, Santa Clara County prosecutors said in a media statement.

But the tips and leads they received led nowhere, and so the case remained unsolved for 47 years.

Until earlier this year, when police say a relative disclosed that Nickerson admitted to stabbing the teacher just minutes after it happened, prosecutors said.

“This marks the end of a terrible and tragic mystery,” Santa Clara County Dist. Atty. Jeff Rosen said in a statement. “Ms. Peterson would have been a senior citizen today if she had not crossed paths with this violent teenager. I wish she was.”

Nickerson became a person of interest in the case just days after Peterson was killed, when he was arrested in an unrelated crime and detectives noticed his booking photo bore a striking resemblance to a police sketch of the teacher’s killer.

The sketch came from a student witness who said they heard Peterson yell for help and saw the killer flee. The same student, however, later disclaimed his statement, according to authorities.

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Police had also been told by a witness that they had seen Nickerson carrying a knife that had “Teacher Dear” written on the side. But under questioning, Nickerson denied having a knife at all, and authorities were unable to corroborate the claim.

Years later, prosecutors noted the retracted statement by the fellow student, as well as another person who said Nickerson confessed to killing Peterson when she confronted him about drug dealing, but neither story was corroborated.

Over the years, authorities say, Nickerson built up a rap sheet that included convictions for kidnapping, armed robbery and assault with a deadly weapon. He was shot and critically injured during an attempted drug robbery in 1984 and committed suicide in 1993.

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