Complex sentence: On January 7, several policemen from Cologne denied statements that the police didn't know about the nationality of the perpetrators, they told the press that "most of them" would have been freshly immigrated asylum seekers.
Split into simpler sentences: On January 7 several policemen from Cologne denied statements, that the police didn't knew about the nationality of the perpetrators. They told the press, that "most of them" would have been freshly immigrated asylum seekers.