The man, who disappeared when he was 16, was reportedly tied to a bed in a tiny, windowless room of the house in Sao Paulo.
Police believe he lived in virtual darkness for two decades in a room without light fittings, while the floor was reportedly covered in human faeces.
'He got up, very impaired and didn't speak a word. We took him outside and he still didn't say anything. We didn't know if he was scared or drugged.
'He wasn't able to identify us as police officers. We called for help and he was taken straight to hospital', the police said.Neighbours in the Guarulhos district of Sao Paulo, southeast Brazil, recalled how Armando was a normal 16-year-old, who liked skateboarding and playing the guitar, when he suddenly disappeared. His friends never saw him again and when they inquire from Armando's family, they were always told he had moved to another part of Brazil where he was building his family and ‘doing well'.