Were other people killed along side the Jewish people in Europe?

Absolutely. The genocidal policies of the Nazis resulted in the deaths of about as many Polish Gentiles as Polish Jews, thus making them co-victims in a Forgotten Holocaust. This Holocaust has been largely ignored because historians who have written on the subject of the Holocaust have chosen to interpret the tragedy in exclusivistic terms--namely, as the most tragic period in the history of the Jewish Diaspora. To them, the Holocaust was unique to the Jews, and they therefore have had little or nothing to say about the nine million Gentiles, including three million Poles, who also perished in the greatest tragedy the world has ever known. Little wonder that many people who experienced these events share the feeling of Nobel Laureate Czeslaw Milosz, who anxious when the meaning of the Word Holocaust undergoes gradual modifications, so that the Word begins to belong to the history of the Jews exclusively, as if among the victims there were not also millions of Poles, Russians, Ukrainians, and prisoners of other nationalities. -- Richard C. Lukas, preface to The Forgotten Holocaust: The Poles under German Occupation 1939-1944