The investigation found out that the criminals helped Moldovan citizens get a job in Germany, using fake Romanian passports.
800 policemen searched 21 offices and houses where they criminals could hide; the searches took place in Hamburg, Bremen Saxony-Anhalt and Lower Saxony.
The three key suspects, two Germans and one Russian, were arrested in Hamburg on May 7. There are five more suspects, including Ukrainian citizens.
Currently, the investigation against 13 suspects is underway, the police say.