Five South Koreans are on trial in Germany over the alleged murder of a relative during an exorcism ritual.
The defendants at Frankfurt state court are aged between 16 and 44, and include the son of the 41-year-old woman who died.
Police discovered the woman's body in a Frankfurt hotel room last December after the suspects called a priest when it became apparent she had died.
Prosecutors claim the defendants wanted to expel a "demon" they believed had possessed the woman, and that she died of asphyxiation as a result of "massive chest compression and violence to her neck".
The trial is scheduled to last until mid-January.
The defendants did not immediately make any statements as the trial opened. In Germany, defendants do not enter formal pleas in trials.
The five accused are believed to practice a form of Christianity with shamanist influences. They arrived in Frankfurt about six weeks before the killing and planned to set up an import-export business, according to reports.