LISTEN: Authorities Release Chilling Phone Call Family Received After Daughter Went Missing 45 Years Ago In South Jersey Cold Case

BURLINGTON CITY, N.J. (CBS) -- Authorities in South Jersey announced a big break in a decades-old missing person's case on Monday. Fourteen-year-old Margaret Fox disappeared in Burlington County back in 1974 and on Monday, the FBI released new evidence they hope leads to her abductor.

Monday is the 45th anniversary of when Fox went missing. It's a case that has haunted the Burlington community, but police say they are still working leads and are hopeful they'll solve the missing persons mystery.

"This case has been passed down to generations of law enforcement," Burlington City Police Chief John Fine said.

Fine made a passionate plea over the 45-year-old missing persons case of Fox.

"In the event the offender is deceased and you know about the whereabouts of Margaret, we ask you we'd like to speak to you," Fine said.

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Authorities say Fox was 14 years old when she disappeared on June 24, 1974. Fox was in eighth-grade at St. Paul's Roman Catholic School in Burlington when she paid for a classified ad in a local newspaper, trying to find babysitting work.

A man responded, saying he would meet her at a bus stop at High and Mill Streets in Burlington, but Fox was never seen again.

"Not knowing what happened to your child is a torture beyond what any of us care to imagine. For 45 years, the Fox family has endured that torture," FBI Assistant Special Agent in Charge Joseph Denahan said.

A few days after her disappearance, Fox's mom received a disturbing phone call. Police just made it public Monday after enhancing the audio with new technology.

"Ten-thousand dollars might be a lot of bread but your daughter's life is the buttered topping," the caller said.

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Police also said Monday that it's possible both Margaret and whoever may have kidnapped her are dead. But they still want to close the case.

This is a rendering of what a 59-year-old Fox might look like today.

If you recognize the man's voice, call police.