Suspect in 1978 murder of San Jose teacher ID'd as 16-year-old boy, authorities say
SAN JOSE, Calif. -- The student suspected of fatally stabbing San Jose teacher Diane Peterson nearly 50 years ago carried a knife inscribed with "Teacher Dear," authorities said Monday when announcing they had identified the suspected killer.
A relative of the teen suspect told San Jose police earlier this year that he came to their home and confessed just minutes after the killing on June 16, 1978.
A family member of Peterson, who asked to be unidentified, thanked investigators for "not giving up for 47 years," according to a release from the Santa Clara County District Attorney's Office.
"Diane was a beautiful and wonderful person who is missed dearly," the relative said.
Peterson was found by a student on the floor near her classroom at Branham High School with a stab wound to the chest. The killing occurred the day after school had recessed for summer, while teachers were cleaning their classrooms for the break, authorities said.
"A student at the time heard Diane calling for help. She was saying help, help, help. That student actually saw the perpetrator flee from the scene," Santa Clara County Deputy District Attorney Rob Baker told ABC7 News on Monday.
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A witness previously told police that the suspect, who was 16 years old at the time, had confessed to stabbing Peterson and that he had been seen with a knife that had "Teacher Dear" written on it. Police at the time weren't able to corroborate the claim.
The suspect, who died by suicide in 1993, was an initial suspect and was booked into jail four days after the killing. His booking photo had a strong similarity to a composite sketch based on eyewitness accounts of the attack, police said.
In 1983, the family of a Branham student told police that their son claimed to have seen the killing and identified him as the suspect. The student later denied making the statement.
In 1984, a witness told police that the teen suspect implicated himself in the killing, saying it was because Peterson found him dealing drugs.
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Between 2023 and 2024, the district attorney's crime lab conducted extensive DNA work on the case to identify the perpetrator but was unsuccessful.
Investigators broke the case this year after meeting with his family member.
In the years following the murder, the suspect was arrested and convicted of armed robbery, assault with a deadly weapon, and kidnapping. He was shot and critically injured in 1984 while attempting to commit a drug robbery. Given the circumstances, no charges were filed, according to the district attorney's office.
"This marks the end of a terrible and tragic mystery," District Attorney Jeff Rosen said. "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."
Editorial Note: ABC7 omitted the name of the suspect since he was a teen at the time of the murder, and has since been deceased
