The case of a Utah teenager murdered more than 50 years ago is finally closed after authorities said Wednesday that DNA evidence confirmed she was a victim of notorious serial killer Ted Bundy.

Laura Ann Aime, 17, was last seen at a Halloween party on Oct. 31, 1974. She left the party to do a convenience store run and never returned, according to the Utah County Sheriff’s Office.

Hikers found the woman’s body about a month later, down an embankment just off a mountain road. It appeared she had been strangled and severely beaten, the office said.

Before his execution in 1989, Bundy admitted to killing Aime, Sheriff Mike Smith said Wednesday.

But authorities declined to accept the confession and determined the case “was unable to satisfactorily convict Bundy based upon the evidence in possession and with the available investigative sciences for the time,” the sheriff’s office said.

At the time, Bundy was studying law at the University of Utah.

A sheriff's office in Utah has "definitive proof" that Ted Bundy murdered a teenage girl in 1974.A sheriff’s office in Utah has “definitive proof” that Ted Bundy murdered a teenage girl in 1974. Credit: AAP

The office said that it began efforts last year to resolve Aime’s cold case using new forensic techniques and DNA test comparisons.

The process confirmed that the DNA evidence recovered from Aime’s body in 1974 belonged to Bundy.

“This case is officially closed,” Smith said during a news conference Wednesday.

Michelle Impala, Aime’s younger sister, remembered Aime as a fun, outgoing older sister.

“I was 12 when Laura died. She was 17. We were really close. We shared a room. We rode horses together. She was very passionate about animals,” Impala, who is now 64, said at the news conference.

“She took me everywhere, as a 12-year-old that was pretty cool to hang out with my older sister.”

Utah County Sheriff’s Sgt. Mike Reynolds, who was involved in reviewing Aime’s cold case last year, described the late teen as “the quintessential daughter of Utah County.”