More than 1000 young people in Denmark are facing charges for distributing sexually explicit material of minors, after Facebook notified authorities of the activity.
They are accused of using the social media site's Messenger app to share around a video clip of two 15 year olds having sex.
Fifteen is the age of consent in Denmark but police have said that sharing the footage could be classified as distributing child pornography.
Inspector Lau Thygesen from Denmark's North Zealand Police said in a statement that the videos were shared "across the country" in autumn last year and the case is "very large and complex".
"We have taken the case very seriously as it has major implications for those involved when such material is spread."
A total of 1004 young people have been accused of spreading the explicit material.
Those that were over 18 were called to police stations to be interviewed and those under 18 were contacted through their parents.
One Danish high school student told the BBC that it is shocking how many teens are unaware that sharing this kind of material can have legal consequences.
"I think it's horrible that so many people don't know what they might share," the student said. "Or that just in general what they have on their computer can have this type of consequence."
Another teen revealed that they were shocked at how quickly the content spread online.
"What surprised me most was the extent of the case, the fact that 1000 people can be included in this case shows how easily videos like this can be spread," the teen said.
Another student told BBC she thinks excitement is a big reason why young people share this kind of material.
"I think there is a lot of suspense. It's exciting and you can be a part of something like 'Have you seen it? Yes I have, I shared it and look at this video'," they said.
"I think it has a lot to do with that."
If the suspects are found guilty they could receive a fine or a 20-day suspended sentence and could have criminal records lasting up to 10 years.