The mother is alleged to have kept her mentally disabled 26-year-old daughter locked up since she was a small child.
ITV News reports that the young woman was found by chance after cops were called to the flat in Rosenheim, southern Germany to carry out an eviction notice.
When they raided the “rubbish-strewn flat”, officers freed the young woman who was in a “physically run-down and neglected state” and tied up behind a locked door.
They believe her mother could have been holding her captive in the room for years, possibly since childhood, police say.
One neighbour, who has not been named, claims she has never seen the 26-year-old despite having lived there since 2003.
Police say the young woman has now been sent to a psychiatric hospital.
Police said a 54-year-old woman, believed to be the captive’s mother, tried to commit suicide as officers tried to enter the flat. She was raced to hospital after suffering severe injuries.
It was only after they gained access to the flat, and broke down the locked door, that cops discovered the young woman.