SALT LAKE CITY — A 66-year-old suspect in the 1977 killing of a Hawaii teenager was released from a Utah jail on Thursday after prosecutors in Honolulu said they weren’t ready to proceed with a murder charge against him.

Gideon Castro was arrested in January at a Utah nursing home on a fugitive warrant for suspicion of second-degree murder in the death of 16-year-old Dawn Momohara. He had waived the right to challenge his extradition during a hearing in Salt Lake City last month. Castro, who is ill, appeared by video from a hospital bed.

While Castro was still awaiting extradition, Honolulu prosecutors told their counterparts in Utah this week that they were not proceeding against him because of “recent complications involving a material witness in this case and the state of the evidence.”

“Please understand we view this as only a temporary setback, and we remain fully committed to continuing our efforts to prosecute this matter in the near future,” Kelsi Guerra, a deputy prosecuting attorney in Honolulu, wrote in a Monday letter to Deputy Salt Lake County District Attorney Clifford Ross.

Utah District Court Judge John Nielsen ordered Castro’s release late Wednesday afternoon. He was released Thursday, said Chris Bronson, spokesperson for the Salt Lake County Sheriff’s Office.

On March 21, 1977, shortly after 7:30 a.m., Honolulu police found the body of Momohara on the second floor of a building at McKinley High School. She was lying on her back, partially clothed with an orange cloth wrapped tightly around her neck and had been sexually assaulted and strangled, police said.

Castro graduated from the Honolulu school in 1976.

An attorney for Castro had said during a hearing last month in Salt Lake City that he intended to fight the charges upon his return to Hawaii, where he is still a resident, according to jail records. It is unclear how long Castro had been in Utah when he was arrested at the nursing home in Millcreek, just south of Salt Lake City.

A McKinley High School graduate who was the school’s band teacher at the time of Momohara’s death said he was disappointed to learn of Castro’s release.

“I guess they’ve got to make sure they have a rock-solid case,” Grant Okamura said.

“In a sense I’m disappointed that they couldn’t at least go to trial but I can understand their nervousness that they don’t want to just haphazardly go into something and have it thrown out.”

Authorities in Hawaii said Thursday that they were continuing with their investigation into Momohara’s killing. No further information was being released at this time, Honolulu police spokesperson Michelle Yu said.

Following Momohara’s death, police released sketches of a person of interest and a possible vehicle described by witnesses as a 1974 or 1975 Pontiac LeMans. But they were unable to identify a suspect, and the case grew cold.

Police used advances in DNA technology to connect Castro to the killing. They had interviewed Castro and his brother in 1977, but they were unable to conclusively link Castro to the killing until obtaining DNA samples in recent years.