BERLIN—Two suspects were arrested in Germany and Slovakia in raids Monday on a group accused of smuggling Vietnamese into Germany and other European countries for large fees that they had to work off in massage parlors, brothels, and other places, authorities said. Police in Berlin arrested a Vietnamese woman who lives in the German capital, while a Slovak woman was detained in Bratislava. They were alleged to be part of a larger group of suspects—several Vietnamese, one German, and two Slovaks—that brought Vietnamese people to Europe on fraudulently obtained visas. They are accused of demanding payments of between 13,000 and 21,000 euros ($15,800 to $25,600), which investigators suspect had to be worked off in nail studios, massage parlors, and apartments used as brothels. A Vietnamese man is suspected of giving hormone injections to women who worked as prostitutes in Germany to prevent them from getting unwanted pregnancies, prosecutors and police …