Hmm never can be sure couse my german is not perfect, but I heard something like:
Pass Kontroll, verzogert, funf und dreisig
and then the same in english, but only about 35 mins delayed (finally 45) I was thinking is some problem with passport controll (strange couse its Schenghen anyway).
When I've travelled few times directly from Amsterdam, there was always couple of German Police man, whos been checking our passport and lagguage sometimes, so when I heard that at Cologne station, just was thinking it was some problem with some passengers and that made this delay.