San Jose teacher's 1978 murder traced to suspect after 47 years

By Sagaya Fernando  | June 4, 2025

 

San Jose, California, USA: Authorities have closed the 47-year-old cold case of a San Jose schoolteacher’s murder, identifying a then 16-year-old boy as the perpetrator decades after the fatal stabbing.

 

Diane Peterson, a teacher at Branham High School, was found with a single stab wound to her chest on 16 June 1978, a day after classes had ended for the summer. Her body was discovered by a student near her classroom while teachers were clearing out rooms for the holidays.

 

On June 2, 2025, the Santa Clara County District Attorney’s Office confirmed that Harry "Nicky" Nickerson, who was 16 at the time, was responsible for Peterson’s death. Although he was an early suspect, prosecutors lacked sufficient evidence to press charges at the time.

 

A press release stated that Nickerson, who was not a student at Branham High, bore a strong resemblance to a police sketch based on witness descriptions. Multiple people over the years alleged he had confessed to the killing. One witness reported seeing him carry a knife engraved with the words "Teacher Dear".

 

In 1983, the parents of a student told investigators that their son had witnessed the murder and identified Nickerson as the assailant. The student later denied making the claim. A year later, another individual said Nickerson had admitted to the crime, alleging that the teacher had discovered his involvement in drug dealing.

 

Despite renewed DNA testing between 2023 and 2024, forensic efforts failed to yield a conclusive match. The breakthrough came when investigators learned that Nickerson had privately confessed the murder to a relative shortly after it occurred. The family member confirmed the account earlier this year.

 

“There was no sexual assault, just a single stab wound, and the incident took place in a semi-public area at the school,” Deputy District Attorney Rob Baker said. “Once we realised that physical evidence was unlikely to support the case, we focused on interviewing people close to Nickerson.”

 

Nickerson had a lengthy criminal history after the murder, including convictions for armed robbery, assault with a deadly weapon, and kidnapping. He was critically injured during a failed drug-related robbery in 1984. He died by suicide in 1993 from a self-inflicted gunshot wound.

 

District Attorney Jeff Rosen stated: “Ms. Peterson would have been a senior citizen today if she had not crossed paths with this violent teenager. I wish she was. Though the perpetrator will not face justice, we are grateful to provide answers and closure to her loved ones.”

 

San Jose Police Chief Paul Joseph added: “While the suspect will never stand trial, this resolution offers a measure of peace to a community that has waited too long. Every victim matters. Every life deserves justice.”

 

Since its formation in 2011, the DA’s Cold Case Unit has solved over 30 historic murder cases, including four this year.

 

A member of Peterson’s family, who requested anonymity, expressed gratitude to investigators for “not giving up for 47 years.” They remembered her as “a beautiful and wonderful person who is missed dearly.”