The father of the two children who died in downtown Hanau in May has been charged with murder.
A spokeswoman for the public prosecutor's office confirmed a report by the Hanauer Gazette at the weekend when asked.
According to the investigation, the prosecution assumes that the 47-year-old man first injured his seven-year-old daughter in the family's home.
The child was later found dead by the police.
Her eleven-year-old brother was discovered on the street, presumably he had panicked and jumped off the balcony on the ninth floor of a high-rise building.
The boy was badly injured and died shortly afterwards in hospital from internal injuries.
The reason for the crime is said to have been the separation of the parents of the two children.
The trial is expected to begin in January.
The father, an Indian, was arrested a few days later by French police in a Paris suburb and extradited to Germany in July.
Officials from the State Criminal Police Office and the Hanau Criminal Investigation Department picked up the man in France and took him to Hanau, where the district court ordered him to be held in custody.
During the interrogation in the district court, the man did not comment on the allegations.
The two siblings had lived with their mother in the high-rise building.
The family moved to Hanau earlier this year.
Family difficulties had already become apparent before the act of violence, which is why the Hanau youth welfare office became active.