The bodies had been in the boxes for “more than several months”, according to the public prosecutor dealing with the case in the Gießen area of Hesse.
The 40-year-old woman who is assumed to be mother to the babies, was on parole for fraud, but was taken back into prison when the bodies of the babies were found at her flat. It seems they were not triplets.
She has told investigators the children were still-born, but tests on the bodies are being conducted to see whether that is right.
The condition in which the bodies were found “is going to make it very difficult to get answers,” said a spokeswoman for the prosecutor on Tuesday evening.
People clearing the woman's flat in Langgöns, Hesse, found the first two bodies in the cellar and called police who found the third in a garage on Wednesday.
The woman has four living children, the youngest of whom was born recently while she was in prison and taken into care.
“Results from the autopsy may take up to several days,” she said, but they should shed some light on when the children died and potentially the cause of death.
The father of the children has been identified but is not the focus of the investigation.