Prosecutors' spokesman Ulrich Bremer said a 26-year-old Algerian was recognised in one photo released yesterday and was arrested in Kerpen, near Cologne.
A 31-year-old Iraqi turned himself in in Hamm, northeast of Cologne, after recognising himself in a photo, Bremer said.
The younger man is accused of being part of a group involved in the sexual assault and attempted robbery of a woman, and the older is suspected of making sexual comments to a woman and her family.
