Former Hawaii lawmaker Suzanne Chun Oakland remembers arriving at school one morning in 1977 to an eerie buzz.

The 15-year-old had met up with girlfriends as usual before class at Honolulu’s McKinley High School when she learned a student named Dawn Momohara had been found dead on the second floor of a school building.

“I don’t know how we got word of it, but everything spread really quickly,” Chun Oakland said.

Chun Oakland didn’t know Momohara, who was 16, but the unsolved death has haunted her and other McKinley students and staff for nearly half a century. That was until last week, when police used advances in DNA technology to arrest a 66-year-old resident of a Utah nursing home.

The suspect, former McKinley student Gideon Castro, was scheduled to make an initial court appearance Friday before a judge in Salt Lake County District Court. He remained in custody Thursday with the bond for his release set at $250,000, according to Salt Lake County Sheriff’s Office records.

Castro’s attorney, Marlene Mohn, did not respond to email and phone messages seeking comment.

Momohara had been sexually assaulted and strangled, police said.

“I was just really sad,” Chun Oakland recalled earlier this week. “I think for our student body, of course there’s that concern that what if he’s still out there and he does it to somebody else.”

On March 21, 1977, shortly after 7:30 a.m., Honolulu police found Momohara dead. She was partially clothed and lying on her back with an orange cloth tied around her neck, said Lt. Deena Thoemmes, of Honolulu Police. A subsequent autopsy ruled Momohara was strangled to death, and the medical examiner said there were signs of sexual assault.

Details from more than four decades ago are fuzzy for 1967 McKinley graduate Grant Okamura, who was the school’s 28-year-old band teacher in 1977, but the morning Momohara was found has remained a core memory.

Momohara’s sister — one of his flute players — arrived at school that day not knowing her sister had been found dead, he recalled. The sister was called to the office and later walked into the band room, devastated.

“The other students were trying to console her,” Okamura said. “At that point, I couldn’t have band. How do you have a class? She just sat there crying.”

She didn’t return to school for weeks afterward.

He doesn’t remember the sister’s name. The Associated Press was unable to make contact with any possible relatives. Okamura said he met Momohara a few times when he let her into the air-conditioned band room to wait for her sister.

The morning before Momohara was killed, she got a call from an unknown male and told her mother she was going to a nearby shopping center with friends. That was the last time her mother saw her, police said.

Police released sketches of a person of interest and a possible vehicle described by witnesses as a 1974 or 1975 Pontiac Lemans. A witness reported seeing the car when he and his girlfriend drove through campus the night before Momohara died. The witness saw a man and the car on the grass near the school’s English building, Thoemmes said.

The witness circled back around but the car and the man were gone.

Police were unable to identify a suspect and the case grew cold, though grief lingered over the campus.

Although police retrieved an unknown man’s DNA sample from the teenager’s clothing, they could not identify a suspect. Authorities would not develop meaningful leads in the homicide until decades later.

In 2019, cold case detectives asked a forensic biology unit to examine several items of evidence from the scene, including Momohara’s underwear. They were able to develop a DNA profile in 2020. Then, in 2023, police received information about potential suspects, two brothers who were interviewed in 1977.

Several days after Momohara was killed, detectives interviewed Castro, who graduated from McKinley High in 1976. He said he met Momohara at a school dance that year and last saw her at a carnival on campus in February 1977. Police interviewed his brother, who also met Momohara at the dance.

In November 2023, Honolulu police went to Chicago, where the brother was living. They “surreptitiously” obtained DNA from one of the brother’s adult children, Thoemmes said.

Lab findings excluded the brother as a suspect, but a DNA sample from Castro’s adult son, and later from Castro himself, proved he was responsible, Thoemmes said.

He was arrested last week at the nursing home where he lived in Millcreek, just south of Salt Lake City, on suspicion of second-degree murder.

Neither Okamura nor Chun Oakland remembered Castro.

Chun Oakland graduated in 1979 and grew up to become a Democratic member of the Hawaii Senate. She said Momohara’s killing bothered her over the years, especially when she would meet victims through her work as a lawmaker or as a board member of the nonprofit Sex Abuse Treatment Center, a statewide program provding services for sexual assault survivors.

Chun Oakland said she is grateful an arrest was possible even after all these years.

“I think the community in general, and our elected officials, they know the importance of trying to preserve the evidence that can someday be able to see justice for that individual or individuals,” she said.