"The girl was put through a number of things to get rid of evil spirits that possessed her, according to certain notions," said prosecutor Daniel Larson to local newspaper Borås Tidning (BT).
Police have previously been unwilling to divulge any details about the case, which occurred in Borås, in southwestern Sweden.
According to BT, suspicions first surfaced in 2004 when an anonymous report arrived at the National Board of Health and Welfare (Socialstyrelsen), but the agency opted not to pursue the matter at the time.
Six years later, in 2010, the agency received new reports that the child was being abused, as well as information indicating that her father had taken her to Skåne to force the evil daemons out of her.
The girl may have been beaten and burned over a long period of time in order to drive out demons. She was also locked up, in order to prevent her from infecting others with her evil spirits, reported the newspaper.
The prosecutor also confirmed that the case is connected to controversial local congregation The River.
"Events which we've investigated occurred on the congregation's premises, so in that sense it is connected," said Larson.
Following a four-hour remand hearing on Friday at Borås' district court, the 33-year-old step mother , who is believed to be the driving force behind the violent exorcism attempts, was remanded in custody on suspicion of gross violation of a person's integrity (grov fridskränkning).
The girl's 37-year-old father was also ordered held on remand on suspicion of being an accomplice to the assault and for false imprisonment.
Attorneys for the father and stepmother told BT that their clients deny having committed any crimes.
The head of The River congregation, Gun Hartikainen, refused to comment on the matter.
"I have nothing to say to you. Have a blessed day. Good bye," she told BT.