Collection 5, Diary of a Young Girl

From the text, we can infer that the prisons have been liquidated..... the prisoners..... possibly killed, as they are no longer available.

We have a new pastime, namely, filling packages with powdered gravy. The gravy is one of Gies & Co.'s products. Mr. Kugler hasn't been able to find anyone else to fill the packages, and besides, it's cheaper if we do the job. It's the kind of work they do in prisons.