The bruised body of a 41-year-old woman was found by staff at Frankfurt's InterContinental Hotel on Saturday morning, a spokesperson for the Frankfurt prosecutor's office told The Local.
Police arrested five family members of the woman in connection with her death, which officials suspect occurred during an attempted exorcism.
"This isn't something that happens often at all," the prosecutor's office spokesperson told The Local.
"It's an extremely unusual case."
Currently in custody are a 44-year-old woman, her son (21), daughter (19) and two 15-year-old boys - one of whom was reportedly the victim's son.
The five are reportedly from South Korea and arrived in Hesse six weeks prior.
The suspects are reported to have tied the woman to the bed and beaten her in the stomach and chest for several hours, prosecutors told DPA on Wednesday.
To stifle her screams, they stuffed a towel into her mouth, causing the woman to eventually suffocate.
The suspects gave information leading to the discovery of the second woman, who was suffering from hypothermia and severe dehydration.
Police found her in a house rented by the suspects in Sulzbach, Hesse.
The home in Sulzbach where the group's alleged second victim was found. Photo: DPA
The 44-year-old woman reportedly talked about an exorcism during initial questioning.
It's not yet clear which religion the suspects and victims belong to, or whether the group was acting on a request from the victim herself, prosecutors said.
Reporting and writing by Hannah Butler