Earlier this week five German cities saw stabbing attacks on the same day with several hospitalised and at least two migrants declared suspects in connection with the attacks.
The attacks have generated considerable media attention in once-peaceful Germany, where this level of violence is unusual.
The first attack occurred in Cologne at around 4:40 am Sunday and came about following a dispute at a local hookah bar.
As the dispute became more aggressive, violence broke out with one of the men involved stabbing another man several times with a sharp object, forcing him to require emergency surgery to save his life, German tabloid Bild reports.