A fourth person was arrested in Paraguay, according to Interpol.
The online platform known as Boystown, hosted on the dark internet, had 400,000 registered users when it was taken offline by an international task force.
The global team led by the Federal Criminal Police – the Federal Criminal Police Office (BKA) – consisted of 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 prime suspects in mid-April who are alleged to have operated and serviced the Boystown platform during the raids on seven properties, Reuters reported.
All 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 in Munich, and a 58-year-old 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 most active users of the website after registering as a member of the platform in July 2019 and posting more than 3,500 times.
Europol said on Monday that several other chat sites used by perpetrators of child sexual abuse had been seized on the same occasion.