Four people were arrested and more than 100 internet servers were taken down worldwide during an international police operation against a network that spreads malicious software, Europol reported on Thursday. The EU law enforcement service called this operation conducted between Monday and Wednesday Operation Endgame, and it is the largest in history against botnets. The investigation was led by Germany, the Netherlands and France, with the participation of several countries that are not part of the EU. Arrests have been made in Armenia and Ukraine, and more than 2,000 domains are now under police surveillance. According to the investigation, one of the main suspects earned no less than 69 million euros (US$74.5 million) in cryptocurrency by renting out websites to cybercriminals to distribute extortion programs.