The Swedish public prosecutor will close the investigation on Thursday into the woman (70) who was arrested near Stockholm for allegedly imprisoning her 41-year-old son for years.
According to the prosecution, there is no evidence that the man was held against his will or that he is the victim of violence.
Swedish media reported after the arrest that the woman allegedly held her son for 28 years.
The man was then transferred to hospital due to ill health and injuries, where he is still being treated.
The mother was suspected of illegal deprivation of liberty and of causing physical harm.
Suspicions against her were toned down on Wednesday after police held talks with the son.
The Swedish was released that same day, three days after her arrest.
The prosecutor now says that a forensic investigation in the apartment in Haninge, a suburb of the Swedish capital Stockholm, has found no evidence that the man was being held there against his will.
There were no locked doors or areas and equipment to tie anyone up.
It also appears that the man's injuries were not caused by violence, but due to his poor health.
"It is very important now to help both people and not to look for a scapegoat," said the prosecution.
The 41-year-old man was found in the apartment by a family member on Sunday after his mother was taken to hospital that day.
Swedish media reported, among other things, that he had inflamed sores on his legs, could barely walk and had limited speech.