Three men have been arrested on suspicion of a gang rape that was broadcast live on Facebook.
Police in Sweden raided an apartment and detained the suspects, who were aged between 18 and 24.
The alleged gang rape of a 30-year-old woman on Sunday took place in Uppsala, about an hour north of the capital, Stockholm, and has shocked the Nordic country.
"This rape was broadcasted live in a Facebook group," police said in a statement.
Several viewers of the live broadcast reported the rape, according to the statement.
A woman who witnessed the assault and reported it to police told Sweden's Expressen newspaper that one of the attackers had filmed everything using a mobile phone and also posted pictures on the Snapchat messaging site.
Police swooped on the apartment in the city and detained the three men while they were still with the victim.
The broadcast is the latest graphic video to bring into focus the complex ethical and policy issues faced by Facebook Live and others.
Facebook Live allows anyone to broadcast a video directly from their smartphone.
Local media reported that the video had been removed and police were appealing for anyone who has a copy of the film to hand it over.
On its website, Facebook says it will "remove content, disable accounts, and work with law enforcement when we believe there is a genuine risk of physical harm or direct threats to public safety."
