A mother and her two daughters are under investigation in Germany for launching paper sky lanterns which police believe may be to blame for a fire at a zoo that killed more than 30 animals.
The women - aged between 30 and 60 - went to a police station in the western city of Krefeld on 1 January after authorities held a news conference about the blaze, which Krefeld Zoo said left "highly endangered species" dead.
Police chief Gerd Hoppmann described the women as "completely normal people who seemed very sensible, very responsible" - and added that it was "very courageous" of them to come forward, saving authorities a tricky investigation.
Mr Hoppmann explained that the women ordered five sky lanterns on the internet and told authorities they believed they were legal in the country.
He added: "They launched the lanterns with good wishes and had no idea what could happen" - saying there was nothing in the product description showing that they were banned.
He said limited details would be given about the suspects, who feared reprisals after receiving threats.
The mini hot air balloons made of paper have been used in Asia for centuries, but unlike fireworks, they are both unusual and illegal in Germany.
Prosecutor Jens Frobel says the women are suspected of negligent arson, which can carry a prison sentence of up to five years.
Investigators believe just one lantern started the fire, which began in a corner of the roof of the ape house in the first minutes of the New Year, before spreading quickly.
They found the other four later, with handwritten good wishes for the New Year attached.
Dozens of animals died in the fire, including five orangutans, two gorillas, a chimpanzee and several monkeys - as well as fruit bats and birds.
They either burned to death or died from smoke inhalation.
Only two chimpanzees - Bally and Limbo - survived, according to Krefeld Zoo director Wolfgang Dressen.
He described the fire as the hardest day the zoo has ever experienced, adding that what happened was an "unfathomable tragedy".
The ape house lacked fire detectors and sprinklers, which were not required when it was built in the 1970s - but the zoo said it had passed a regular fire protection check just a few months ago.
The building's roof had been renovated after a hailstorm a few years ago and plexiglass was added.
Mr Hoppmann said while investigators were confident the sky lantern was to blame, they will look at other factors that may have contributed to the blaze, such as dry fallen leaves on the roof.
Investigators plan to carry out tests to help find out why it spread so quickly.