I am trying to locate my father's u.s. naturalization papers in order to obtain my german citizenship. I have everything I need except the u.s. naturalization paper. The german authorities are waiting only for this to be able to grant the citizenship based on the fact that, as Jews, my family was forced to leave Germany in the 1930's. I have tried to obtain this paper through U.S. Homeland Security. It has been a year and they are asking for more information as they can't find it. It seems to me there must be another way to find this paper.
Does anyone have a suggestion?

Submit form N-600 with $460 fee and other supported documents as specified in the instruction part of the form. Attach a cover letter stating who are you and why do you want to obtain this document, etc. All must be done by your father. He should be able to receive it within 10-12 weeks.

I currently have a U.S. Passport but would like to obtain a Naturalization document that was destroyed in a flood years ago, which is always good to have as a back up.