A father in Germany has found the bodies of six teenagers, including his son and daughter, in his secluded garden hut in Bavaria, BBC reported.
The five young men and a woman aged 18 and 19 had been having a party outside the town of Arnstein on Saturday night.
The hut's owner went to look for the teenagers when they failed to reappear on Sunday.
Police say the cause of the deaths is unclear, but that there are no initial indications of a violent crime.
The father called emergency services for help but it was too late. A neighbour told German media that his daughter had been celebrating her 18th birthday.
The brick-built building was some distance outside Arnstein and the area was covered in snow.
Police are trying to find out whether a wood-burning stove used to heat the secluded building had led to the deaths. One theory is that they may have died of carbon monoxide poisoning.
"The circumstances remain unclear," said police spokesman Bjorn Schmitt on Monday. "We don't want to get involved in any speculation."
A criminal investigation has been launched and a post mortem examination will be carried out into the cause of the teenagers' deaths.