After the death of an 88-year-old, the public prosecutor's office and police in Dresden are investigating the 62-year-old son.
The mother's body was found walled up in a basement in early June.
There is an initial suspicion of intentional homicide, the investigating authorities said on Friday.
The man is accused of killing his mother about six to twelve months ago.
Both lived in a house in Riesa in Saxony northwest of the state capital Dresden.
The 62-year-old was found helpless and seriously injured in the house on June 1 after a fall and taken to a hospital.
Because the mother wasn't in the house and the neighbors hadn't seen her for a long time, a closer look was taken, said a spokesman for the public prosecutor's office.
The woman was found in the basement.
An autopsy initially gave no indication of a non-natural cause of death.
It therefore remains for the time being with an initial suspicion, it said.
The investigations continued.
All traces are now being evaluated according to the public prosecutor's office.