HONOLULU, Hawaii (Island News) — Humans can lie, but DNA doesn’t.

After nearly 50 years, the Honolulu Police Department (HPD) made an arrest in the 1977 killing of Dawn Momohara. She was found sexually assaulted and strangled inside a Honolulu high school.

“A suspect was arrested for a murder that occurred in Honolulu nearly 50 years ago,” said HPD Lieutenant Dee Thoemmes

The body of 16-year-old Dawn Momohara was found partially clothed with an orange cloth wrapped around her neck on the second floor of McKinley High School’s English building. The date, March 21, 1977. A witness told police he saw a man, described as in his teens or early 20s, on campus the same night Dawn died. With a composite sketch, police at the time interviewed Gideon Castro and his brother but they denied the crime.

“Gideon graduated from McKinley High school in 1976. He stated Dawn was friends with him and his brother William. He said Dawn called him occasionally when he was still attending McKinley and he last saw her at the McKinley carnival in February 1977 where they talked for about 15 minutes,” Thoemmes said.

The case stayed cold until 2019 when new forensic DNA technology was able to obtain the genetic profile for male bodily fluids found on Dawn’s clothing. Police then took samples from both Gideon and his brothers’ children in 2023, and found a match.

“After initial testing from the FBI, the sample was given to HPD for testing and comparison. Analysis showed that Gideon’s son was the biological child of the unidentified male,” Thoemmes said.

Police credit the closure of the case to technological advancements in DNA analysis.

“Definitely it was the DNA the increase in technology of DNA and what we can do with samples from 1977 to what we can do with them today,” Thoemmes said.

Castro was arrested at a Utah nursing home Tuesday morning. He is being extradited back to Honolulu to face murder charges. HPD is reaching out to the Momohara family to close this tragic chapter.