An American scientist who went missing last week on the Greek island of Crete and was later found dead in an abandoned World War II bunker was suffocated, authorities said Wednesday, as new details emerged about where her body was discovered.

Suzanne Eaton, a 59-year-old molecular biologist at the Max Planck Institute in Dresden, Germany, was last seen on July 2 near the port of Chania, on the Greek island of Crete.

Colleagues at the conference had told authorities they believed she had gone for a run in the area.

Greek police discovered her body Monday in a man-made cave that was used as a bunker during the Nazi occupation of Crete, located about 6 miles from where Eaton was last seen.

On Wednesday, coroner Antonis Papadomanolakis said that Eaton died as a result of a “criminal act.” An examination of Eaton’s body determined she died as a result of suffocation.

“What is definite is that we are talking about homicide. Also, there was no sign of death by gun,” an unidentified official in the medical examiner’s office told the Associated Press.

The 59-year-old’s body was discovered in a cave in a rural area near Chania, located on the westernmost side of Crete, when tourists were exploring the cave.

Eaton had been attending a scientific conference in Crete. The Max Planck Institute, where she worked, called her death a “tragic demise.”