The father found the bodies of his daughter, son and four others in a garden house in Bavaria.
German prosecutors have ordered postmortem examinations on the bodies of six teenagers found dead at a garden house in Bavaria.
The owner of the building in Arnstein found the bodies of his son, daughter and four other men aged between 18 and 19 on Sunday morning.
Police said there was no clear cause of death, but had found no evidence of a violent crime.
“I think it was a birthday party of young people as it happens at any location quite often. Nothing suspicious, really, it is just a tragedy you can’t find words for,” said Franz-Josef Sauer, Deputy Mayor of Arnstein.
A neighbour told German media that the girl had been celebrating her eighteenth birthday.
The building was heated by a wood burning stove, which has prompted detectives to investigate the possibility of carbon monoxide poisoning.