Exterior view of the Federal Criminal Investigation ( Bundeskriminalamt, or BKA) building in Wiesbaden, Germany.
CNN  — 

German police have arrested three people in connection with one of the world’s largest platforms containing child sex abuse materials, prosecutors said Monday.

A fourth person was arrested in Paraguay, according to Interpol.

The online platform, which was known as Boystown and was hosted on the dark web, had 400,000 registered users when it was taken offline by an international taskforce.

The global team, spearheaded by the German Federal Criminal Police – the Bundeskriminalamt (BKA) – included the European Union Agency for Law Enforcement Cooperation (Europol) and law enforcement agencies from the Netherlands, Sweden, Australia, Canada and the United States.

Police arrested three main suspects accused of operating and maintaining the Boystown platform during raids on seven properties in mid-April, Reuters reported.

All of the suspects are male German nationals, according to Europol, who said on Monday that a 40-year old man was arrested in the west German city of Paderborn, a 49-year-old man was arrested in Munich and a 58-year-old man was arrested in Paraguay.

A fourth suspect, a 64-year-old man from Hamburg, was arrested on suspicion of being one of the site’s most active users, having registered as a member of the platform in July 2019 and posted more than 3,500 times.

Europol also said on Monday that several other chat sites used by perpetrators of child sexual abuse had been seized on the same occasion.

CNN’s Stephanie Halasz and Kara Fox contributed to this report.