A woman whose body was found dumped in a Minnesota ditch was murdered, an autopsy shows, and one of her acquaintances is in custody.

But the circumstances surrounding 19-year-old Kathryn Rose Anderson's killing remain a mystery — and authorities say there could be other suspects out there.

Anderson, of Eagan, Minn., was discovered by a passerby Thursday in a trench along a county road northwest of Owatonna, Minn. Police launched an investigation into who the woman was and how she died.

They identified her on Friday, when an autopsy revealed that she died of "homicidal injuries." Authorities several states away in Tulsa, Okla., arrested a person of interest Friday afternoon who they say knows Anderson.

They didn't release the name of the acquaintance in custody and said there may be more suspects in the young woman's baffling murder. A host of questions remain unanswered in the case — which the Steele County Sheriff's Office and the Minnesota Bureau of Criminal Apprehension are handling.

Anyone with information about Anderson's whereabouts late Wednesday and early Thursday is urged to call: (866) 878-7964 or (507) 451-8232.

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The Associated Press contributed to this report.