FRANKFURT (Reuters) - German investigators have shut down the world’s second largest criminal online trading platform and detained three German men suspected of running it, the Frankfurt public prosecutor’s office said on Friday.

The online marketplace, named “Wall Street Market”, was used to trade drugs, private data, falsified documents and malware and had more than 1.15 million customer accounts and over 5,400 registered sellers, the prosecutor’s office said in a statement.

The three men, aged 22, 29 and 31, were detained on April 23-24, it said, adding that Germany’s federal criminal investigation office, or Bundeskriminalamt, had secured the platform’s server infrastructure.

The men, who investigators believe took payments of 2-6 percent of sales made on the platform, were detained after covert operations involving U.S. and Dutch law enforcement agencies, and the European Union’s Europol agency.

Investigators had focused on the three men since March.

Cyber specialists at the Bundeskriminalamt started taking “operational measures” after the suspects switched the platform into maintenance mode on April 23 and started transferring customer funds deposited in the marketplace to themselves, the prosecutor’s office said.