DNA testing has led to the arrest of a former classmate of a Hawaii high school sophomore who was found dead at the school on March 21, 1977.

The Honolulu Police Department announced the arrest of Gideon Castro, now 66, last week for the murder of 16-year-old Dawn Momohara, NBC News reported. He was found in a Utah nursing home and charged with second degree murder.

Honolulu Police Lt. Deena Thoemmes said that Momohara was found “lying on her back, partially clothed” on the second floor of the English building of McKinley High School. Examinations and other evidence revealed she had been raped and strangled.

Police said Momohara left home the day of her death, telling her mother she was going to a shopping center with friends. She wasn’t seen alive again. Investigators conducted multiple interviews, but the case grew cold with no suspects.

That began to change in 2019 with advances in DNA testing, and the following year developed a DNA profile of an unknown male from sperm found on Momohara’s shorts.

Federal investigators assisted Honolulu police an matched the DNA to Castro earlier this month. He is in custody in Utah and awaiting extradition to Honolulu.

“I want to thank all the individuals and agencies that made today’s arrest possible,” Thoemmes said. “Thank you all for your dedication and commitment to the tireless pursuit of justice for Dawn and the Momohara family.”