The activity may constitute distribution of child pornography, the Danish National Police said on Monday. The case is “very large and complex,” Police Inspector Lau Thygesen said. “We’ve taken the matter very seriously as it has big consequences for those involved.”

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The charges follow calls in Denmark for greater efforts to clamp down on revenge porn and distribution of private material after young women last year detailed in local newspapers how their lives had been destroyed by the publication of photos and video intended only for their partners. The crackdown also comes amid a shift in tolerance toward such acts as the #MeToo movement gains traction.

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“It’s our impression that young people know very well that the consequences are substantial for the victims when this type of material is distributed,” Flemming Kjaerside, a police superintendent for Denmark’s National Crime Center, said in the statement. “But they perhaps don’t know that it is also punishable, and they can be convicted of distributing child porn.”

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Danish police said they began their investigation after Facebook (FB) notified U.S. authorities of two explicit video clips and a photograph of the couple on its chat platform Messenger last year. U.S. authorities in turn notified European police. While most of those charged distributed the material a couple of times, others distributed it several hundred times, Danish police said.