Cold Case: San Jose high school teacher's killer identified as 16-year-old boy
Share this @internewscast.com

SAN JOSE, Calif. (KRON) — Nearly 50 years after a young teacher was found stabbed to death inside a San Jose high school on the first day of summer break, cold case investigators identified her killer publicly for the first time on Monday.

Branham High School teacher Diane Peterson was stabbed to death by a 16-year-old boy, Harry “Nicky” Nickerson, on June 16, 1978, the Santa Clara County District Attorney’s Office said. Nickerson had a knife with the words, “Teacher Dear,” written on it, investigators said.

One day after the 1977-1978 school year ended, Branham High School teachers were cleaning their classrooms for summer. A student found Peterson lying on the floor near her classroom with a stab wound in her chest.

Branham High School teacher Diane Peterson (Image courtesy the Peterson family via SCCDAO)

Investigators cracked the cold case after meeting with Nickerson’s family member this year, according to the DA’s office. Minutes after the killing, Nickerson went to their home and confessed to stabbing the teacher, a family member admitted to police.

“Just this year, investigators learned that he had confessed the killing to a family member. Nickerson committed suicide in 1993,” SCCDAO wrote.

Harry “Nicky” Nickerson is seen as a teenager in an undated photo. (Image via SCCDAO)

Nickerson was not a Branham High School student, Deputy District Attorney Rob Baker told KRON4. While detectives have never established a firm motive, “detectives at the time theorized that Diane inadvertently interrupted a drug deal on campus the day after school let out for the summer,” Baker told KRON4.

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.”

Nickerson was arrested four days after the killing for an unrelated incident, Baker said. “He spontaneously accused the police of trying to ‘pin’ the murder on him, he denied killing Diane, and denied owning a knife,” Baker told KRON4.

Police took a mugshot of the 16-year-old boy in June 1978, and it bore a strong similarity to a composite sketch based on eyewitness accounts of the high school attack, prosecutors said.

A police sketch of Diane Peterson’s killer (left). Harry “Nicky” Nickerson is seen as a teenager in an undated photo (right). (Images via SCCDAO)

In 1983, a Branham High School student’s family alerted police that their son claimed to have seen Peterson’s violent death and identified Nickerson as the person responsible. The student, however, later denied making that statement. In 1984, another witness told police that Nickerson confessed to killing Peterson, but police were unable to corroborate the claim.

After high school, Nickerson continued committing more crimes, including kidnapping, assault with a deadly weapon, and armed robbery, prosecutors said.

“He was shot and critically injured in 1984 while attempting to commit a drug robbery. Given the circumstances, no charges were filed. He died in 1993 from a self-inflicted gunshot wound,” SCCDAO wrote.

Between 2023 and 2024, the DA’s Crime Lab conducted extensive DNA work on the case in an attempt to identify Peterson’s killer. Unlike other recently-solved South Bay cold cases, forensic investigators were unable to make a DNA match. Instead, the break in the case came from Nickerson’s family member coming forward to police.

“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. No matter how much time passes, we will continue to seek the truth. Every victim matters, and every life deserves justice.”

The DA’s Cold Case Unit was established in 2011 and solved over 30 cold case murders from as early as 1969. The Peterson case is the fourth cold case homicide solved by the DA’s Office in 2025.

A family member of the teacher said, “Diane was a beautiful and wonderful person who is missed dearly.”

Share this @internewscast.com
You May Also Like

Exposing the Chaos: Insider Revelations Unveil the Shocking Reality of Local Nursing Home

TYBEE ISLAND, Ga. — A group of both former and current staff…

Escaped Inmate Recaptured After Daring Leap from Jail Transport Van

A man described as a serious violent felon is once again in…

Holocaust Exhibit Premieres in Champaign, Bringing Museum Experience to Visitors

CHAMPAIGN, Ill. (WCIA) – In a significant collaborative effort, three organizations came…

Jack Nicklaus Triumphs: Legendary Golfer Secures $50M Victory in Defamation Battle Against Ex-Business Partners

MIAMI (AP) — Legendary golfer Jack Nicklaus has emerged victorious in a…

Hampton Fire Chief Shares Insights on Response Times Following Helene Storm

In Elizabethton, Tennessee, the Hampton Volunteer Fire Department is grappling with delays…

New Development Near Forsyth Park to Feature Offices and Underground Parking

In Savannah, Georgia, there’s a buzz around a newly cleared plot near…

Security Breach: Man Arrested for Crashing Vehicle into White House Gate

A man was apprehended late Tuesday night after crashing his car into…

Forensic Experts Investigate Human Skull Discovered at JC Golf Course; DNA Analysis Next Step

In Johnson City, Tennessee, police are delving into the discovery of a…

RCSO Revamps Deputy Hiring Process After Series of Arrests: What You Need to Know for 2025

AUGUSTA, Ga. ()- Concerns have been raised regarding the recruitment process for…

Revolutionary Champaign Clinic Addresses Common Yet Overlooked Disorders Affecting Millions

CHAMPAIGN, Ill. (WCIA) — A groundbreaking clinic in Central Illinois is now…

Port Wentworth Ice Cove Celebrates Milestone with Beam Topping Ceremony

PORT WENTWORTH, Ga. – Tuesday marked a significant milestone for Port Wentworth’s…

Israel Confirms Identities of Additional Hostage Victims Amid Vance’s Diplomatic Mission to Meet Netanyahu

TEL AVIV – In a solemn update, Israeli authorities have confirmed the…