The family members, who are between the ages of 15 and 40, are accused of killing their 41-year-old female relation on December 5th 2015 in the Intercontinental Hotel in Frankfurt am Main.
One of the accused, who was 15 at the time of the crime, was the victim's son, prosecutors say.
The brutal murder began in the early morning hours of the winter day, when the victim began to start swinging her arms around, talking to herself and physically attack the people around her “for unexplained reasons”.
It was at this point that the accused decided to perform an exorcism on her, prosecutors allege.
After pushing her to the ground, two of the male members of the family sat on her arms and pinned her to the floor.
Over a period of at least two hours they then inflicted “pains and torture on her body that went far beyond what is necessary to kill someone,” prosecutors say.
The woman's 44-year-old cousin is alleged to have stuffed a towel and a clothes hanger into her mouth in order to stop her from screaming.
The eventual cause of death was serious damage to her chest and injuries around her neck, prosecutors say.
The victim's sister was later found in a state of hypothermia and extreme thirst in a house in southwestern Germany, Spiegel reports.
Since the crime, all of the accused have been held in custody.
The five are reportedly from South Korea and had arrived in Hesse weeks prior to the woman's killing.
While it has not been confirmed to what religion the family belonged, police confirmed that after the 'exorcism', the 44-year-old woman called a pastor from the Korean Evangelical Zion Church, who then alerted the hotel and authorities.
Psychiatric examinations have not revealed signs of mental illness on which a plea of reduced responsibility could be made, according to the prosecution.