WELD COUNTY, Colo. (CBS4) – The death of Jonelle Matthews, who disappeared 35 years ago, will be investigated by the 19th Judicial District Grand Jury. Officials in Colorado made the announcement in a news release on Tuesday.

Matthews was 12 when she was last seen at her home in Greeley on Dec. 20, 1984. Oil field workers found her remains on July 23, 2019 at an oil site in Weld County.

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Jonelle Matthews (credit: CBS)

In June, CBS4 and the Greeley Tribune filed requests for copies of the autopsy report which was sealed by the Weld County Coroner’s Office. The county opposed the request, arguing it could compromise their investigation.

(credit: CBS)

District Court Judge Shannon Lyons approved a partial release and ruled that details that could potentially compromise the ongoing investigation would not be released while the investigation is continuing. The redacted information includes the cause and manner of death.

However, the report states states Matthews’ skeletal remains were mixed with “abundant dirt and debris” when they were delivered to the McKee Medical Center. The skull and mandible were “largely intact.”

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(credit: CBS)

Dental records helped investigators identify the remains as that of Matthews.

The Weld County District Attorney’s Office and the Greeley Police Department will assist in the investigation. A decision to bring criminal charges or indictments against potential defendants are typically made in grand juries.

No one has been publicly arrested or charged with Matthews’ death. Due to rules surrounding a grand jury case, investigators are not saying if there is a suspect.

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Danielle Chavira