Prominent American microbiologist Suzanne Eaton, who went missing after going on her daily run, died from being suffocated, authorities said.

Investigators on the Greek island of Crete, where Eaton was attending a professional seminar, now say her death was a criminal act.

The 59-year-old scientist with the Max Planck Institute in Germany disappeared more than a week ago in rugged terrain around the conference site. Relatives believed she had gone jogging because her running clothes and shoes were missing from her room, which contained all of her other belongings including her passport and cellphone.

Her body was found Monday, and new details have emerged since then.

The remains were discovered in a Nazi-era bunker popular with hikers, authorities said. A system of handmade caves honeycomb the area, remnants from when Nazis occupied the island during World War II. 

Local reports said Eaton was covered in a rough fabric like burlap and her body had small cuts and bruises. An autopsy determined her cause of death was asphyxiation, according to media reports.

Greek investigators from the capital of Athens have flown in to assist the homicide investigation, authorities said. 

Friends and relatives established a Facebook page after she went missing to raise funds for search efforts. Her family has not commented publicly about her cause of death. 

Eaton was married to British scientist Tony Hyman. The couple has two sons, who accompanied their father to Crete after Eaton vanished to help search for her. 

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