Two people were arrested Friday in connection with a massive New Year’s fireworks explosion in Honolulu, Hawaii, that killed at least three people and injured two dozen more.

Dawn Momohara was 16 years old when her body was found on the second floor of McKinley High School in Honolulu in 1977. For decades, detectives had failed to identify a suspect in the murder case but now, thanks to a breakthrough in DNA technology, they have arrested a former classmate, police confirmed.

DNA evidence helped lead long-stymied detectives to a suspect in the murder of Dawn Momohara, 16, who was strangled and found dead at her high school.

A grim discovery was made at a Hawaii high school in 1977, one that would pose a mystery for decades. Student Dawn Momohara, 16, was found dead inside McKinley High School on Monday, March 21, 1977, according to the Honolulu Police Department.