Story highlights No conclusions drawn about cause of death pending additional review, coroner's office says

Otto Warmbier died days after he was returned to United States from North Korea

(CNN) The family of American college student Otto Warmbier objected to an autopsy, leaving the former North Korea detainee's official cause of death a mystery for the time being.

The Hamilton County Coroner's Office in Ohio confirmed that it received and examined the 22-year-old's body after his death on Monday

The Warmbier family's "objection to an autopsy was honored," the office said, and only an external examination was performed.

The coroner's office reviewed medical records from the University of Cincinnati Medical Center and the air ambulance service that helped bring Warmbier from Pyongyang to Cincinnati after 17 months. "Extensive" conversations with his treating physician took place, too.

"No conclusions about the cause and manner of Mr. Warmbier's death have been drawn at this time as there are additional medical records and imaging to review and people to interview," the statement said.

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