A ring of fraudsters who allegedly arranged sham marriages between Portuguese women and Nigerian men to obtain EU residence permits was busted on Tuesday, according to German police.
At least 40 residences were searched in Berlin alone during the coordinated mass raids across Germany.
Raids were also conducted in Potsdam, Frankfurt and the eastern town of Goerlitz.
The federal police said there were at least 70 known cases so far with more expected.
In Berlin, police arrested four women between ages of 46 and 64, and one 50-year-old man who was said to be the head of the ring and had contacts in Portugal, helping them to recruit women from there.
The Nigerian men paid up to15, 500 dollars for the documents to the ring, which shared some of the money with the Portuguese women.
Portuguese police aided in the investigation by prosecutors in Berlin, which had been ongoing since November 2016.